Center of mass and momentum Questions and Answers

A particle moving with constant speed parallel to a smooth wall over a smooth horizontal plane is acted upon by an impulse of 2 N-s perpendicular to its motion. The particle of mass 0.5 kg consequently changes its speed to 5 m/s and undergoes a collision with the wall such that after collision the speed becomes 3√2 m/s. Find the value of coefficient of restitution between the particle and the wall.

A uniform rod AB of mass 3m and length 2a has a point mass 2m attached at B. The rod is free to rotate in vertical plane about a smooth horizontal axis passing through point A. An impulse of J = m √21 ag is given at B perpendicular to rod as shown. Which of the following statements is/are correct? Moment of inertia of whole assembly about the axis through point A is 12ma² Distance of centre of mass of the system from point A is a 7/6a The rod turns an angle of 60° before coming to instantaneous rest for first time The rod completes full circle in vertical plane

What is the momentum of a 92 kg football player who is moving at 6.2 m/s?

An investigation of an automobile crash suggests that vehicle A was moving at 52 mph toward the south and vehicle B was moving at an unknown speed toward the north, when the two cars collided, sticking together after the collision. Vehicle A weighs 1350 lbs., and vehicle B weighs 1893 lbs. If the cars did not move significantly after their collision, find the initial speed of vehicle B in mph.

A 0.151 kg glider is moving to the right on a frictionless, horizontal air track with a speed of 0.730 m/s. It has a head-on collision with a 0.309 kg glider that is moving to the left with a speed of 2.11 m/s. Suppose the collision is elastic. Find the magnitude of the final velocity of the 0.151 kg glider.

During an in-class demonstration of momentum change and impulse, Mr. H asks Jerome (102 kg) and Michael (98 kg) to sit on a large 14-kg skate cart. Mr. H asks Suzie (44 kg) to sit on a second 14-kg skate cart. The two carts are placed on low friction boards in the hallway. Jerome pushes off of Suzie's cart. Measurements are made to determine that Suzie's cart acquired a post-impulse speed of 9.6 m/s. Determine the expected recoil speed of Jerome and Michael's cart.

Cheryl (mass= 50 kg) and Jared (mass = 62 kg) occupy separate 36-kg bumper cars. Cheryl gets her car cruising at 3.6 m/s and collides head-on with Jared who is moving the opposite direction at 1.6 m/s. After the collision, Cheryl bounces backwards at 0.5 m/s. Assuming an isolated system, determine Jared's post-collision speed.

A 6 kg object starts at rest. It is then pushed by a 10 N force for 8 seconds. A.How much initial momentum does the object have? B.Calculate the impulse that acted on the object. C. Since impulse equals a change of momentum, how much momentum did it gain? D. How much momentum does it have afterwards? E. Calculate the final velocity of the object.

A 20.-kilogram mass moving at a speed of 3.0 meters per second is stopped by a constant force of 15 newtons. How many seconds must the force act on the mass to stop it? 1.3 sec 5.0 sec 0.20 sec 4.0 sec

A force of 10. newtons acts on an object for 0.010 second. What force, acting on the object for 0.050 second, would produce the same impulse? 5 Newtons 5 Newtons 2 Newtons 20 Newtons

Car C is a 1900-kg car traveling at 25 m/s. It collides with Car D, a 2450-kg car moving 12 m/s in the same direction. The two cars stick together upon colliding. What is the new speed of these cars?

Ball A is 0.40 kg and it collides with Ball B of mass 0.60 kg. Ball A initially moves to the right with a velocity of 1.0 m/s while Ball B moves to the left at 2.0 m/s (or -2.0 m/s). After the collision, Ball A moves to the left at 2.60 m/s. What is the velocity of Ball B in

238 kg kg, A uranium nucleus U may stay in one piece for billions of years, but sooner or later it de- cays into an a particle of mass 6.64 x 107 and 234Th nucleus of mass 3.88 x 107 and the decay process itself is extremely fast (it takes about 10-20 s). Suppose the uranium nucleus was at rest just before the decay. If the a particle is emitted at a speed of 6.67 x 106 m/s, what would be the recoil speed of the thorium nucleus? Answer in units of m/s.

Two particles A and B of mass m and one particle C of mass M are kept on the x-axis in the order ABC. Particle A is given a velocity vî. Consequently there are two collisions, both of which are completely inelastic. If the net 7 energy loss because of these collisions is 7/8 of the initial energy, the value of M is (ignore frictional losses) (A) 8m (B) 6m (C) 4m (D) 2m

A stationary cannon of mass "100m" fires a cannonball of mass "m" at speed "v." What is the recoil speed of the cannon? Assume that frictional forces are negligible and the cannon is fired horizontally. A. 1/101 v B. 1/50 v C. v D. 1/100 v

From a solid sphere of radius R a quarter of sphere is cut out as shown. The centre of mass of remaining part is at distance √2 R/n from centre of sphere. Find value of n.

A 22.6-kilogram child emerges from the end of a tall playground slide at a speed of 7.65 m/s, where she collides head-on with her 90.7-kilogram father, who is waiting at rest near the foot of the slide. The two grab each other, thereby "sticking together" in the collision. Immediately after the collision is complete, what is the final speed (in meters/second) of the father-and-child together?

A car moving with 30 m/s collides head on with a stationary car. The cars stick together after the collision. Bon cars have mass 1,000 kg. a) What is the speed of the cars after the collision. b) Compare the kinetic energy of the two cars before and after the collision. How much kinetic energy is lost in the collision? c) Will the amount of kinetic energy lost be different if both cars travel with 15 m/s towards each other and then collide head on?

A ball with a mass of 0.15 kg and a velocity of 5.0 m/s strikes a wall and bounces straight back with a velocity of 3.0 m/s. What is the change in momentum of the ball? Remember, the ball is changing direction, so the final velocity is negative!! A. -0.15 kg-m/s B. -1.20 kg-m/s C. -7.50 kg-m/s D. -0.30 kg-m/s

A 1,227 kg car slows from 20.1 m/s to 2.3 m/s. What is its change in momentum? Round your answer to the nearest 0.1. Do not add units.

A 1.06 kg plastic ball is rolling forward at 0.7 m/s. It collides with a second plastic ball of mass 2.12 kg, also rolling forward at 0.8 m/s. After the collision, both balls continue rolling at different speeds. The 2.12 kg ball is now rolling at 1.73 m/s. What is the new velocity of the 1.06 kg ball? Round your answer to the nearest 0.01. Do not add units.

A 1 kg plastic ball is rolling forward at 0.61 m/s. It collides with a second plastic ball of mass 1.9 kg, also rolling forward at 0.22 m/s. After the collision, both balls continue rolling at different speeds. The 1.9 kg ball is now rolling at 0.85 m/s. What is the new velocity of the 1 kg ball?

A 1.54 kg plastic ball is rolling forward at 1.12 m/s. It collides with a second plastic ball of mass 0.87 kg, also rolling forward at 0.81 m/s. After the collision, both balls continue rolling at different speeds. The 1.54 kg ball is now rolling at 0.53 m/s. What is the new velocity of the 0.87 kg ball?

A rubber ball with a mass of 0.30 kg is dropped onto a steel plate. The ball's velocity just before impact is 4.5 m/s (down) and just after impact is 4.2 m/s (up). What is the change in the ball's momentum? A. -4.0 kg-m/s B. -12 kg-m/s C. -2.6 kg m/s D. -0.09 kg-m/s

A rifle with a mass of 3.2 kg shoots a 0.29 kg bullet. If the rifle's recoil velocity is 7.4 m/s, how fast is the bullet moving? Round your answer to the nearest 0.1. Do not add units.

Colin, who has a mass of 38.2 kg, is roller skating toward his mom at -2.3 m/s. Mom, with a mass of 72.8 kg is skating toward Colin at 4.4 m/s. When they collide, Mom grabs Colin's hand and they continue skating together. How fast are they skating together? Round your answer to the nearest 0.1. Do not add units.

A 2 kg mass moving to the right makes an elastic head-on collision with a 4 kg mass moving to the left at 4 m/s. The 2 kg mass reverses direction after the collision and moves at 3 m/s. The 4 kg mass moves to the left at 1 m/s. What was the initial velocity of the 2 kg mass? A. 1 m/s to the left B. 3 m/s to the right C. 4 m/s to the right D. 4 m/s to the left

A 6 kg mass moving at 3 m/s collides with a stationary 4 kg mass. Afterwards the 4 kg mass moves off at 2 m/s. a. What is the final momentum of the 6 kg mass? b. What is the final velocity of the 6 kg mass?

A golf club has 10 kg m/s of momentum when it hits a golf ball that is at rest. After the collision, the golf club has a momentum of 1 kg m/s and the golf ball has a momentum of 9 kg m/s. Which of the following comparisons is TRUE about the change in momentum of the two objects? A. there was no change in momentum for the two objects B. the change in momentum was unequal for the two objects C. the change in momentum is the same for the two objects D. the change in momentum is equal and opposite for the two objects

A 0.3 kg plastic ball is rolling forward at 0.8 m/s. It collides with a second plastic ball of mass 1.85 kg, also rolling forward at 0.96 m/s. After the collision, both balls continue rolling at different speeds. The 1.85 kg ball is now rolling at 1.37 m/s. What is the new velocity of the 0.3 kg ball? Round your answer to the nearest 0.01. Do not add units.

Four particles of masses 4.00kg, 3.00kg, 3.50kg and 5.50kg are located at (4.00,5.00), (3.25, 6.20), (-2.00, 6.50) and (2.50, -7.0) respectively. a) where is the center of mass located? b) What is the magnitude and direction of center of mass?

NASA is launching a probe (m = 500 kg) at a small asteroid (m = 2000 kg). The asteroid is traveling at 100 m/s, and the probe is moving perpendicularly toward it with a speed of 400 m/s. Unfortunately, the landing gear does not work right, so the probe bounces off the asteroid. After the collision, the asteroid is knocked off its course by 71° and is now going 165 m/s. If the probe's speed is now 300 m/s, in what direction is it going?

A 65.0 kg ice skater standing on frictionless ice throws a 0.15 kg snowball horizontally at a speed of 32.0 m/s. At what velocity does the skater move backward? A. 0.07 m/s B. 0.30 m/s C. 0.15 m/s D. 1.20 m/s

A 3.8 kg bird slows from 6.8 m/s to 4.3 m/s while looking for a good tree to land in. What is its change in momentum? Round your answer to the nearest 0.1. Do not add units. YES, your answer should be negative. YES, you must include the negative sign.

A 908 kg car slows from 30.3 m/s to 7.8 m/s. What is its change in momentum? Round your answer to the nearest 0.1. Do not add units. YES, your answer should be negative. YES, you must include the negative sign.

A train car of mass 3,366 kg sits at rest on the track. A second car of mass 3,161 kg moving at 4.2 m/s slams into it and they stick together. What is the combined speed of the train cars after the collision? Round your answer to the nearest 0.1. Do not add units.

1. Weylan is at the county fair playing some of the games. At one booth, he throws a 0.75-kg ball forward with a velocity of 21.0 m/s in order to hit a 0.50-kg bottle sitting on a shelf, and when he makes contact the bottle goes flying forward at 20.0 m/s. What is the velocity of the ball after it hits the bottle?

Aliya is rolling along on her 4.0-kg long board with a constant speed of 3.0 m/s when she jumps off the back and continues forward with a velocity of 2.0 m/s relative to the ground. This causes the long board to go flying forward with a speed of 15.5 m/s relative to the ground. What is Aliya's mass?

Running at 2.0 m/s, Marty, the 45.0-kg quarterback, collides with Biff, the 90.0-kg tackle, who is traveling at 7.0 m/s in the other direction. Upon collision, Biff continues to travel forward at 1.0 m/s. How fast is Marty knocked backwards?

A 100 N applied force is at 22.5 degrees to the 2 meter radius of a rotating disk. What is the torque?

Weylan is at the county fair playing some of the games. At one booth, he throws a 0.75-kg ball forward with a velocity of 21.0 m/s in order to hit a 0,50-kg bottle sitting on a shelf, and when he makes contact the bottle goes flying forward at 20.0 m/s. What is the velocity of the ball after it hits the bottle?

Johnny and Francis are participating in the Roller Skating dance championship. While 73.0-kg Johnny roller skates backwards at 3.0 m/s, 57.0-kg Francis jumps into his arms with a velocity of 5.0 m/s in the same direction. How fast do they roll backwards together?

A 320.-kg reindeer stands in the middle of the railroad tracks, frozen by the lights of an oncoming 10,000.-kg train that is traveling at 10.0 m/s. The engineer sees the reindeer but is unable to stop the train in time and the reindeer rides down the track sitting on the cowcatcher. What is the new combined velocity of the reindeer and train?

A system consists of three particles with these masses and velocities: mass 3.00 kg, moving north at 3.00 m/s; mass 4.00 kg, moving south at 4.40 m/s; and mass 7.00 kg, moving north at 2.00 m/s. What is the total momentum of the system? Take north as the positive axis. Enter a positive answer if the total momentum is due north and a negative answer if the total momentum is due south.

Two skaters collide and grab on to each other on frictionless ice. One of them, of mass 77.0 kg, is moving to the right at 4.00 m/s, while the other, of mass 62.0 kg, is moving to the left at 2.50 m/s. What is the magnitude of the velocity of these skaters just after they collide?

A rifle has a mass of 5.20 kg and it fires a bullet of mass 10.0 g at a muzzle speed of 820 m/s. What is the recoil speed of the rifle as the bullet leaves the gun barrel?

On a frictionless horizontal air table, puck A (with mass 0.253 kg) is moving toward puck B (with mass 0.375 kg), which is initially at rest. After the collision, puck A has velocity 0.120 m/s the left, and puck B has velocity 0.652 m/s to the right. What was the speed vAi of puck A before the collision? Calculate AK, the change in the total kinetic energy of the system that occurs during the collision.

A 4,000-kg truck traveling with a velocity of 10 m/s due north collides head-on with a 1300-kg car traveling with a velocity of 20 m/s due south. The two vehicles stick together after the collision. a. What is the momentum of each vehicle prior to the collision? b. What are the size and direction of the total momentum of the two vehicles after they collide? c. What is the velocity immediately after the collision?

A 0.100-kg ball collides elastically with a 0.300-kg ball that is at rest. The 0.100-kg ball was traveling in the positive x-direction at 5.80 m/s before the collision. What is the velocity of the 0.300-kg ball after the collision? If the velocity is in the -x-direction, enter a negative value.

Consider two less-than-desirable options. In the first you are driving 30 mph and crash head-on into an identical car also going 30 mph. In the second option you are driving 30 mph and crash head-on into a stationary brick wall. In neither case does your car bounce off the thing it hits, and the collision time is the same in both cases. Which of these two situations would result in the greatest impact force? A. hitting the other car B. hitting the brick wall C. The force would be the same in both cases. D. We cannot answer this question without more information. E. None of these is true.