FILE CATEGORY QUESTION SYNOPSIS
 1 Mechan Can you explain to my husband and my brother why thin tires produce more traction than wide tires and why race car drivers prefer wide tires with no tread over thin tires with deep treads. I have tried many times with the typical male response "you don't understand racing." They seem to think that race drivers like the wide, treadless tires because they produce more traction. Duh!! Can you explain in terms that they would understand? I give up.
 3 Mechan What is the maximum acceleration a car can undergo if the coefficient of static friction between the tires and level ground is 0.80?
 6 Mechan we are supposed to build a contraption to hold an egg that is light and will prevent an egg from being broken when put in the contraption and dropped...Do you have any suggestions on successful ways to build this?
 7 Mechan A 50kg high wire artist carries a weighted pole as illustrated. Her center of gravity is 80cm above the high wire and the two 23kg masses are located 120cm vertically below the wire. Find the vertical location of the center of gravity of the walker and the weighted pole relative to the high wire. Is this case of stable or unstable equilibrium.
 9 Mechan How long would a 100W light bulb burn, on weighing 140g(if the mass was converted to energy)?
 11 Mechan A man and a bicycle have a total mass of 100 kg. He is cycling at a constant 8m/s up a hill that makes a 4 degree angle with the horizontal direction. What power must the rider expend against gravitational forces?
 12 Mechan what is acceleraton
 13 Mechan An airplane travels 80m/s as it makes a horizontal circular>turn which has a 0.80-km radius. What is the magnitude of the resultant>force on the 75- kg pilot of this airplane (in kN)?
 15 Mechan e have the length of a car tire's skid mark. We are guessing that the co-efficient of friction for car tires is about .5 or so. What is the proper formula for the calculating of the velocity of this vehicle?
 16 Mechan A wheel is being rolled along a level path with a constant speed of ten m/s. A small lump of mud stuck on the wheel suddenly breaks losse when it is at the top of the wheel. If the wheel has a diameter of two m, how far ahead of the axle is the lump when it strikes the path?
 17 Mechan If you had to decide between regular width tires with no treads or tires with (both are called slicks), which would you choose for better breaking ability? In drag racing, wide slicks are prefered for the rear tire's, why?
 18 Mechan Do things of different weight fall at the same speed when dropped from the same height? Will they fall at the same time on the ground?
 21 Mechan I want a picture of the insides of a photocopier. I realize that this is not as easy as just putting a mirror on the machine. I doubt that the reflection of the inside will come out as an image. I am thinking that it may come out all black. Or will it? I was hoping that you could explain exactly what does happen.
 23 Mechan How much work is done by a person lifting a 2.0 kg object from the bottom of a well at a constant speed of 2.0 m/s for 5.0 s (in kJ)?
 24 Mechan A 5000 LB AIRPLANE LOOPS AT A SPEED OF 200 MI/HR. fIND THE RADIUS OF THE LARGEST CIRCULAR LOOP POSSIBLE, AND THE FORCE ON THE PLANE AT THE BOTTOM OF THE LOOP.
 26 Mechan I am most obliged if someone can clear my doubts on pulley system:1. Why is a movable pulley more efficient than a fixed pulley? 2. What governs the efficiency of a movable pulley system?
 27 Mechan I think this question is Kinematics...A jet pilot sets his compass due east. After 30 min, during which he maintained a constant speed of 400km/h with repect to the air, he finds himself flying over a city located 220 km east and 20km south of his point of departure, Determine the wind velocity in magnitude and direction.
 28 Mechan Hi! I'm building an egg car for physics. Dropping something weighing 1 kg. from 1 meter, my car (with an egg as its passenger) must go exactly 6 meters. I must also utilize a braking system. Any ideas?
 29 Mechan A tennis ball is thrown from ground level with velocity Vo directed 30 degrees above the horizontal. If it takes the ball 1.0 second to reach the top of its trajectory, what is the magnitude of the initial velocity?
 30 Mechan A 60 kg woman bends 90 degrees forward from the waist, keeping her legs vertical. The centre of gravity for her upper body is located 70 cm from her hips. If two-thirds of her mass is in her upper body, how far forward from the line of her legs is her new centre of gravity?
 31 Mechan A ball rolls off a cliff that is 10 m high. If the ball lands 5 m away from the edge a. how long does it take to hit the ground? b. what is it's initial speed? c. what will be it's final velocity (give both the magnitude and direction)
 32 Mechan Willy obtains an inclined plane with theta= 36.9 degrees and length s=1.00 m. He releases block A from rest at the top of the plane at the same instant he relases and identical block B from te bottom with an initial speed Vo. Willy observes that just before the blocks collide, their speeds are equal and opposite. The coefficient of kinetic friction between blocks and plane is Uk=0.3. How far up the plane in cm did this collision occur?
 34 Mechan 30. An oar is held by a rower at .35m from the oarlock. The oar makes contact with the water at an average of 1.3 m from the oarlock. If the force applied by the rower on the oar is 80N. what is: a)the force of the oar on the water, and b)the force on the oarlock. the anwers are a) 22N and b) 100N I need to know the method to getting the answer correct!!!
 35 Mechan Sliding friction is more than rolling friction because
 37 Mechan given angular velocity, time and radius how to you figure distance along the perimeter?
 38 Mechan At room temperature, an oxygen molecule, with mass 5.31 x 10-26 kg, typically has a KE of about 6.21 x 10-21 J. How fast is it moving?
 39 Mechan A 0.5 Kg rock is tied to a 75 cm string and a person swings it ina vertical circle. The rock goes around at a constant 1.5 revolutions per second. 1. determine the tension in the string when the rock is at the top of the circle. 2. at the bottom of the circle. 1 rev = 2 PI
 40 Mechan Two identical balls are traveling toward each other with speeds 4.0 and 7.0 m/s, and they experience an elastic head-on collision. Obtain the velocities (magnitude and direction) of each ball after the collision.
 43 Mechan Ok, I'm studying physics over the summer on my own, and I bought the text book, but sometimes the answers in the book don't seem reasonable. I'd like a 2nd opinion. The question is: "Agent Tim, flying a constant 185 Km/h horizontally in a low-flying helicopter, wants to drop a small explosive onto a master criminal's automobile traveling 145 Km/h (same direction) on a level highway 88.0 meters below. At what ANGLE (with the horizontal) should the car be in his sights when the bomb is released?" By using the formula:[ TAN(-1)angle = -9.80 t / horizontal velocity ] ........ i get -75 degrees. Answer in book is -61.8 degrees. am i wrong, or is the book wrong?
 44 Mechan How do you convert from grams to newtons? In my case, there is 50 grams.
 48 Mechan The radius bone in a forearm has an average effective cross-sectional area of 1.33 x 10 to the -4 meters squared. How much compressive force can it withstand before fracturing?
 49 Mechan A Boeing 747 Jumbo Jet has a length of 57m. The runway on which the plane lands intersect another runway. The width of the intersection is 25.0m. The plane decellerates through the intersection at a rate of 5.70 m/s^2 and xlears it with a final speed of 45.0m/s. How much time is needed for the plane to clear the intersection.
 52 Mechan I seem to get different answers from this for this question. A small car travelling at a constant speed of 20ms-1 on a horizontal road is subjected to air resistance of 570N and road friction of 150N. a) What power providded by the engine of the car is used to keep it in motion at this speed? b) If the effieciency of the cars engine is 25%, at what rate is the chemical energy in the fuel being transformed? c) If 1 Litre of fuel provides 3.3 � 107 J of chemical energy when it is burned, how much fuel is used by the car if it travels at this speed for 100km?
 53 Mechan what is acceleraton
 54 Mechan A plane, travelling at 800 m/s and 1000 m above the earth, drops a bomb weighing 500 kg. How long (in seconds) will it take the bomb to strke the earth and how far (in meters) will the bomb travel before striking the earth?
 55 Mechan Do things of different weight fall at the same speed when dropped from the same height? Will they fall at the same time on the ground?
 56 Mechan why when a 15cm chalk dropped horizontally to the floor will break into 3 parts?
 57 Mechan A block is put on a horizontal table with which it has a coefiicient of friction of 0.25. While on theis table the block is pushed up against a spring such that the spring is compressed and the block is stationary. The block is now released and it slides 60 cm across the table before coming to a stop. Now the same experiment is repeated except that the spring is compressed twice as much as before. What is the distance the block slides across the table in this new case?
 58 Mechan I am most obliged if someone can clear my doubts on pulley system: 1. Why is a movable pulley more efficient than a fixed pulley? 2. What governs the efficiency of a movable pulley system?
 59 Mechan A 3.00-g sample of an unknown type of radioactive material has decreased after two days to the point that 2.52g remain. (a) What is the half life of this material?
 60 Mechan 30. An oar is held by a rower at .35m from the oarlock. The oar makes contact with the water at an average of 1.3 m from the oarlock. If the force applied by the rower on the oar is 80N. what is: a)the force of the oar on the water, and b)the force on the oarlock the anwers are a) 22N and b) 100N I need to know the method to getting the answer correct!!!
 61 Mechan it's not a textbook problem. just been driving me up the wall. two cars, drivng towards each other (1-d). 25 m/s and 35 m/s respectively. cars are 225m apart and hit the brakes, both decelerating at 4.0 m/s^2 ... when do they collide and what's their relative velocities on impact?
 62 Mechan A falling stone takes 0.30s to pass a window which measures 2.1m top to bottom. From what height did the stone fall?
 131 Mechan A sign on a rectangular board is 62 cm wide, 29cm high and has a mass of 9kg. The board can swing on an axle through the upper left hand corner, but it is held in position by a rope attached to the upper right hand corner. IF the rope leans to the left, making, forming an angle of 60 degrees with the vertical. What will be its tension? If the rope breaks allowing to the sign to swing down, what will be its initial angular acceleration? Hint: Use the parallel axis theorem to find the moment of inertia.
 137 Mechan A 2kg block is released with an initial speed of 5 m/s along a horizontal tabletop toward a light spring with force constant 10 N/m. The coefficient of Kinetic friction between block and table is 0.25, and the block is initially 2.0 m from the spring. a) What is the max compression of spring? b) How far from the spring is the block when it comes to rest?
 139 Mechan Lets say a guy is hanging still from a single vertical rope. He starts to climb upwards. I understand that the tension upwards is initially equal to the downward force mg so that the guy is stationary. But how is it that he is able to pull himself upwards with a velocity that he initiated into the system without there being a net positive force upwards? I can calculate the problems by using newtons laws and plugging stuff in, but conceptually it seems strange to me. Please help. s=distance The confusion started when I had to work several power problems of this climbing rope type where P=W/T= ma(s)/T where we must assume a=9.8
 140 Mechan A double atwood's machine has mass one on pulley one an
 141 Mechan A 10 Kg crate is pulled up a rough incline with an initial speed of 1.5 m/s. The pulling force is 100 N parallel to the incline, which makes an angle of 20 degrees with the horizontal. If the coefficient of kinetic friction is .4 and the crate is pulled a distance of 5 meters. a) what is the change in kinetic energy of the crate? b) what is the speed of the crate after it is pulled 5 meters? The text says the answer for a) is 150 Joules and for b)5.6 m/s. The wierd thing is that when I calculated these questions excluding friction those are the answers I got. When I formulated an equation including friction I got smaller numbers. Please help, I'm taking this independant study and have to figure everything out alone.Thanks.
 142 Mechan A mass, M, starts from rest and slides down the frictio
 147 Mechan Frictionless pulley? What bout the tension on the rope?
 148 Mechan A helicoptor rotor blade can be considered a long thin rod, If each of the three rotor blades is 3.37 m long and has a mass of of 160 kg, calculate the moment of inertia of the three rotor blades about the axis of rotation. How much torque must the motor apply to bring the blade up to a speed of 5.o rev/s in 8.0 s/
 151 Mechan A ball is thrown straight upward and rises to a maximum height of 16 m above its launch point. At what height above its launch point has the speed of the ball decreased to one-half its initial value?
 167 Mechan A 30 g ice cube at its melting point is dropped into an insulated container of liquid nitrogen. How much nitrogen evaporates if it is at its boiling point of 77 K and has a latent heat of vaporization of 200 kJ/kg? Assume for simplicity that the specific heat of ice is a constant and is equal to its value near its melting point.
 172 Mechan The question I have is conceptual. Am I correct in assuming that if a solid object equally as dense as water is placed gently on the surface of the water water it will sink until it is slightly below the surface of the water and then be at equilibrium whereas an object that is less dense will just float. Moreover, if the object is slightly MORE dense will it accelerate downward even if it is ONLY slightly more dense than the water?
 173 Mechan A 3.0-kg particle has a velocity of (3.0i-4.0j) m/s. Find its x and y components of momentum and the magnitude of its total momentum.
 174 Mechan A 7.00 kg bolwing ball moves in a straight line at 3.00 m/s. How fast must a 2.45g Ping Pong ball move in a straight line so that the two balls have the same momentum?
 175 Mechan A child bounces a superball on the side walk. The linear impulse delivered by the sidewlak to the ball is 2.00N.s during the 1/800 s of contact. What is the magnitude of the average force exerted on the ball by the sidewalk?
 176 Mechan A superball with the mass of 60g is dropped from a height of 2.0m. It rebounds to a height of 1.8 m. What is the change in its linear momentum during the collision with the floor?
 177 Mechan The force Fx acting on a 2.0kg particle varies in time
 178 Mechan In a slow pitch softball game, a 0.200kg softball
 180 Mechan A garden hose is held in the manner shown in Figure P9.
 182 Mechan (a) if the momentum of an object is doubled in magnitud
 183 Mechan A 50kg football is thrown with the speed of 15 m/s. A s
 184 Mechan A car is stopped for a traffic signal. When the light turns green, the car accelerates, increasing in speed from zero to 5.20 m/s in 0.832 s. What is the linear impulse and average force dose a 70 kg. passanger in the car experience?
 185 Mechan Water falls without splashing at a rate of 0.25 liter/s from a height of 60 m into a 0.75 kg bucket on a scale. If the bucket id originally empty, what does the scale read after 3.0s?
 192 Mechan A potter's wheel, a thick stone disk of radius 0.50m an
 193 Mechan A uniform solid sphere of radius r is placed on the ins
 194 Mechan A uniform rod of weight w and length L is supported at
 195 Mechan A vaulter holds a 29.4-N pole in equilibrium by exertin
 196 Mechan A pendulum of length 1.00 m is is released from an ini
 197 Mechan Consider an undamped forced oscillator at resonance so
 199 Mechan A solid sphere (radius =R) rolls without slipping in a
 200 Mechan A 2.00 kg block hangs without vibrating at the end of a
 201 Mechan help
 203 Mechan Show that is a torsional pendulum is twisted through an
 204 Mechan The mass of the deuterium molecule (D2) is twice that o
 205 Mechan A mass m1= 9.0 kg is in equalibrium while connected to
 206 Mechan A long thin rod of mass M and length L oscillates about
 207 Mechan Consider a damper oscillatior as illustrated in Figure
 208 Mechan A horizontal plank of mass m and lenghtL is pivoted at
 209 Mechan A horizontal platform vibrates with simple harmonic mot
 210 Mechan A block rests on a flat plate that executes vertical si
 211 Mechan A large passanger of mass 150kg sits in the car of Prob
 212 Mechan A weight of 40.0 N is suspended from a spring that has
 213 Mechan Calculate the resonant requencies of (a) 3.00kg mass at
 214 Mechan A 2.00kg mass atached to a spring is driven by an exter
 215 Mechan A pedulum of length 1.00m is released froman inital ang
 216 Mechan Show that the time rate of change of mechanical energy
 217 Mechan Consider the specified single piston engine in Figure P
 218 Mechan While riding behind a car traveling at 3.o m/s you moti
 219 Mechan A clock balance wheel has a period of oscillation of 0.
 220 Mechan A simple pendulum has a lenght of 3.00m. Determine that
 221 Mechan A simple pendulum has a lenght of 3.00m. Determine that
 222 Mechan Consider the physical pendulum of Figure 13.11 (a) If i
 223 Mechan A mass is attached to the end of a string to form a sin
 224 Mechan A meter stick, suspended at one end by a 0.50m long lig
 225 Mechan A simple pendulum has a period of 2.50s (a) what is its
 226 Mechan A 2.00kg mass is attached to a spring and placed on a h
 227 Mechan The amplitude of a system moving in simple harmonic mot
 228 Mechan A bullet of mass 10.0g is fired into and embeds in a 2.
 229 Mechan A particle that hangs from a spring oscillated with an
 230 Mechan A 1.0 KG MASS IS ATACHED TO A HORIZONTAL SPRING THE SPR
 231 Mechan A piston `in an autommobile engine is in simple harmoni
 236 Mechan Describe the working of a color television set.
 256 Mechan Dear tutor: This is a question from the Oxford University entrance exam 1987: A car of mass 'm' moves without friction on a circular track in a vertical planes so that the centre of mass of the car is deistance 'r' from the centre of the circle. The car moves under gravity and the speed 'v' at the base of the track is just sufficient to allow a complete circuit without leaving the track. Obtain an expression for 'v' involoving the radius 'r' and the acceration due to gravity, 'g'. the solution that I got (which I think is wrong) is that the kinetic energy lose from the bottom of the circle is equal to the potential energy gain at the top of the circle. so iin thsi case: 1/2mv*2 = mgh (where h is 2r) then I can find v, BUT, I think this is wrong because this also means that the potential energy lose from the top of the circle is equal to the kinetic energy gain by the car when it reaches the bottom again, which means the car will carry on move around the circle as the track has no friction. Can you tell me what is wrong with my idea and guide me to the right idea? Thank you very much for all your help, I hope I can hear from you as soon as possible.
 257 Mechan A pebble is dropped into a well and 3 s later a splash is heard. The speed of sound in air is 340 m/s. How long does it take for the pebble to hit the water? How long does it take for the sound to reach the human What is the depth of the well??
 267 Mechan Note: the book is available in PS or PDF here: http://hw.serv.ph.utexas.edu/books Cubic Velocity Relationship The velocity of a particle moving along the x axis is given by v(sub x) = for t > 0, where a = 32m/s^2, b = 2m/s^4, and t is in s. What is the acceleration of a(sub x) of the particle when (after t = 0) it achieves its maximum displacement in the positive x direction?
 275 Mechan vENUS IS AN AVERGE DISTANCE OF 1.08 TIMES 10 TO THE 8KM FROM THE SUN. ESTIMATE THE LENGTH OF THE VENUSIAN YEAR USING THE FACT THAT THE EARTH IS 1.50 TIMES 10 TO THE 8KM FROM THE SUN ON THE AVERAGE.
 276 Mechan In the 100 meter dash a sprinter accelerates from rest to a top speed with an acceleration whose magnitude is 2.68 m/s squared. After achieving top speed, he runs the remainder of the race without speeding up or slowing down. If the total race is run in 12.0 seconds, how far does he run during the acceleration phase?
 286 Mechan A rifle is aimed horizantely at a target 100ft away. The bullet hits the target .75 inches below the aiming point. (a)what is the bullets time of flight? (b)what was the muzzle velocity?
 287 Mechan Two soccer players start from rest, 48m apart. They run
 288 Mechan On a dry road a car with good tires may be able to brak
 292 Mechan why is a massive cleaver more effective for chopping vegetables than an equally sharp knife?
 293 Mechan The chimney of a stationary toy train consists of a ver
 294 Mechan If my weight is 127lbs. What is my mass in kilograms? A
 295 Mechan Does a 2-kg iron brick have twice as much inertia as a
 301 Mechan A ball which is thrown vertically upward reaches a particular height after a time t(1) on the way up and a time t(2) on the way down. Prove that a) the initial velocity with which the ball was thrown has a magnitude o.5g(t(1)+t(2)) and b) height H=.5gt(1)t(2). t(1)=time 1, and t(2)= time 2.
 302 Mechan From fundamental physical constants (including
 303 Mechan Mr Physics Person I've been working on this problem and i just dont get it. ok you have....Now imagine that there is a weight on the right side and the left is attatched to the wall. Is the weight on the left going to be 2 times the tension on the right or just the tension on the right to balance the weight? Agggggghhhhh help!!!
 307 Mechan When a droplet of oil spreads out on a smooth water surface, the resulting "oil slick" is approximately one molecule thick. An oil droplet of mass 9.00*10^(-7) kg and density 918 kg/m^3 spreads out into a circle of radius 41.8 cm on the water surface. What is the diameter of an oil molecule?
 308 Mechan A speedy tortois can run at 10.0 cm/s, and a hare can r
 309 Mechan The new BMW M3 can accelerate from zero 50 60 mi/h in 5
 310 Mechan The minimum distance required to stop a car moving at 3
 311 Mechan A roller coaster moves 200 ft horizontally, then travel
 325 Mechan A teenager has a car that accelerates at 3.0 m/s^2 and
 326 Mechan Speedy Sue driving at 30 m/s enters a one-lane tunnel.
 327 Mechan A hot air balloon is travelling vertically upward at a
 328 Mechan A stone falls from rest from the top of a high cliff.
 329 Mechan An airplane starting from airport A flies 300 km east,
 330 Mechan Indiana Jones is trapped in a maze. To find his way ou
 331 Mechan Another scheme to catch the roadrunner has failed, and
 332 Mechan Does an object dropped out of a moving car take longer
 336 Mechan An engineering student wants to throw a ball out of a t
 337 Mechan A motorist is traveling at 18.0 m/s when he sees a deer
 338 Mechan 3. [HRW.2.8.87P] A hot-air balloon is ascending at the
 339 Mechan 3. [HRW.2.8.87P] A hot-air balloon is ascending at the
 340 Mechan 1. [HRW.3.2.3E] A person walks in the following pattern
 341 Mechan Radio signals travel at 3x108 m/s or 0.30 km/ms. Suppo
 344 Mechan 1)Is it possible for an object to have zero velocity bu
 346 Mechan Masses, pulleys, and a force, yet no numbers...
 348 Mechan A rock, starting from rest and falling freely, falls th
 349 Mechan A ball is thrown vertically upward with an initial spee
 351 Mechan How many grams of copper are required to make a hollow
 352 Mechan Assuming that 70 percent of the Earth's surface is covered with water at an average depth of 1 mile, estimate the mass of the water on Earth in kilograms.
 353 Mechan The diameter of our disk-shaped galaxy, the Milky Way, is about 1.0 x 10^5 lightyears. The distance to the galaxy nearest our own is about 2.0 million lightyears. If we represent the Milky Way by a dinner plate 25 cm. in diameter,determine the distance to the next dinner plate.
 354 Mechan How do you begin to even start a problem like the fol
 357 Mechan a projectileis fired at an angle so that both the horiz
 360 Mechan A place kicker must kick a football from a point 36m fr
 361 Mechan Dear PhysicsTutor I'm doing a science project where
 362 Mechan 1. The speedometer of an accelerating car is read as t
 363 Mechan 1. Prove that for any object which is uniformly accerl
 364 Mechan Two aircraft are travelling in the same line in the same direction. At the instant that they are 2.0 km apart, the one which is in front is travelling at 200 km/h, and the one which is behind is travelling at 300 km/h. The lead plane has an acceleration of 2.0 km/h/s, and the second one an acceleratinon of 1.0 km/h/s. Calculate when the second one will be 1.0 km from the first one. answer: 4.7 x 10 s, or 1.5 x 10^2 s
 365 Mechan Just as a traffic light turns green, a waiting car star
 367 Mechan A physicist finds that his car is stuck in the sand and
 372 Mechan A softball pitcher hurls a .250-kg ball around a vertic
 373 Mechan Daniel works for the circus part time on weekends. At a
 376 Mechan I am in AP Physics C and am having some trouble with a
 378 Mechan The pulleys in Fig. P4.8 are frictionless and have negl
 379 Mechan A student analyses an accelerating merry-go-round. A
 380 Mechan A small block of mass m slides along the frictionless l
 381 Mechan From a bridge, one bullet is dropped while the other on
 384 Mechan A space station in the form of a large wheel, 159 m in
 385 Mechan You are standing on the edge of a ravine that is 11.8 m
 386 Mechan An athlete swings a 5.85kg ball horizontally on the end
 392 Mechan A cylinder lying horizontally in the corner of a room,t
 393 Mechan in what ways are sound and light waves similar, or diff
 394 Mechan Two bodies were thrown simultaneously from the same poi
 396 Mechan People say tides are caused by the moon's attraction.
 405 Mechan Addition of Vectors using components?
 429 Mechan One stone is dropped from the roof of a building. 2.00 seconds later, another stone is thrown down at an initial speed of 30.0 m/s, and it is observed that the two stones land at the same time. How long did it take the first stone to reach the grou
 436 Mechan I want to find an equation that can predict the path of a know mass with initial velocity (v), accelerated due the gravitational force by the sun. In other words, I want an equation of displacement as a function of time, with changing acceleration(due to gravitational force).
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