An object at rest explodes, breaking into two pieces. One piece (m2) has six times the kinetic energy of the other piece (m1).   (a) What is the ratio of the masses of the two pieces?      m1/m2 = ?

An explosion breaks a rock into three parts in a horizontal plane. Two of them go off at right angles to each other. The first part of mass 1 kg moves with a speed of 12 ms1 and the second part of mass 2 kg moves with 8 ms-1 speed. If the third part files off with 4 ms- speed, then its mass is?

In the figure below, a 3.1 kg box of running shoes slides on a horizontal frictionless table and collides with a 1.8 kg box of ballet slippers initially at rest on the edge of the table, at height = 0.40 m. The speed of the 3.1 kg box is 5.0 m/s just h before the collision. If the two boxes stick together because of packing tape on their sides, what is their kinetic energy just before they strike the floor? ។ h

Two objects are on a collision course. Object #1 has a mass of 10.2 kg and an initial velocity of 16.7 m/s i. Object # 2 has a mass of 5.4 kg and an initial velocity of --4.7 m/s i. If the system is isolated and the objects stick together upon colliding, what amount of energy is lost in the collision?

answer is vf= 1.0 m/s.

A lumberjack is standing on a log floating on a lake. She starts from rest, then runs along the log to the end, when she jumps from the first log onto a second. After landing safely on the second log, she slows down and ends up standing on the second log. Both logs both have masses of 150 kg each and the mass of the lumberjack is 70 kg. The lumberjack reaches a speed of 7.0 m/s relative to the shore during her jump. What is the speed of the lumberjack after she has stopped on the second log? You may assume the drag of the water on the logs is very small. Please answer in units of m/s.

Particle A and particle B are held together with a compressed spring between them. When they are released, the spring pushes them apart, and they then fly off in opposite directions, free of the spring. The mass of A is 4.00 times the mass of B, and the energy stored in the spring was 46 J. Assume that the spring has negligible mass and that all its stored energy is transferred to the particles. Once that transfer is complete, what are the kinetic energies of each particle? (a) particle A --------- J(b) particle B --------- J

A lumberjack is standing on a log floating on a lake. She starts from rest, then runs along the log to the end, when she jumps from the first log onto a second. After landing safely on the second log, she slows down and ends up standing on the second log. Both logs both have masses of 150 kg each and the mass of the lumberjack is 70 kg. The lumberjack reaches a speed of 7.0 m/s relative to the shore during her jump. What are the speeds of the two logs and of the lumberjack after she has stopped on the second log? You may assume the drag of the water on the logs is very small.

In the figure, a 4.6 kg box of running shoes slides on a horizontal frictionless table and collides with a 3.0 kg box of ballet slippers initially at rest on the edge of the table, at height h = 0.78 m. The speed of the 4.6 kg box is 2.9 m/s just before the collision. If the two boxes stick together because of packing tape on their sides, what is their kinetic energy just before they strike the floor?

A 20 kg block with a speed of 10m/s collides with a 4kg block that has a speed of 5m/s in the same direction. After the collision, the 4 kg block travels in the original direction with a speed of 7 m/s  (a) What is the velocity of the 20 kg block immediately after the collision? (b) By how much does the total kinetic energy of the system of two blocks change because of the collision? (c) Suppose, instead, that the 4kg  block ends up with a speed of 8 m/s What then is the change in the total kinetic energy?