Exam 7: Linear Momentum

A 1200 kg car is moving at 5.0 m/s EAST. It strikes an 1800 kg car at rest. The cars undergo an elastic collision and move in the EAST or WEST direction. The velocity of the 1800 kg car after the collision is

A water hose has a flow rate of 3.0 kg/s of water. If the speed of the water as it leaves the hose is 5.0 m/s, then the magnitude of the additional force required to hold the hose as a result of the water being expelled is

A 100 kg mass, initially at rest, is blown apart into two 50.0 kg pieces. After the blast, the two masses are moving apart with a relative velocity of 100 m/s. The total kinetic energy after the explosion is

An open boxcar has a mass of 30,000 kg and is moving on a level railroad track at 4.00 m/s. 1,000 kg of water falls straight down into the boxcar. The speed of the boxcar after the water falls into it is

A 4.00 kg ball is moving at 2.00 m/s to the WEST and a 6.00 kg ball is moving at 2.00 m/s to the NORTH. The total momentum of the system is

A model rocket with a mass of 500 grams is launched straight up. It achieves a speed of 20.0 m/s in 2.00 seconds. Ignoring any change in mass of the rocket due to expelled fuel, and neglecting air resistance, the average thrust force of the engines on the rocket is

If the momentum of a ball is doubled, then the kinetic energy is

An airplane has a mass of 8,000 kg and is flying at 150 m/s in level flight. The airplane drops 1,000 kg of water on a fire below. The speed of the airplane after dropping the water is

A 140 g baseball with a velocity of 25.0 m/s is hit by a baseball bat and leaves at 30.0 m/s in the opposite direction. If the ball was in contact with the bat for 12.0 ms, what was the average force on the ball?

An astronaut in a space suit is motionless in outer space. The propulsion unit strapped to her back ejects some gas with a velocity of magnitude 50 m/s. The astronaut recoils with a velocity of 1.0 m/s in the opposite direction. If the mass of the astronaut and space suit after the gas is ejected is 120 kg, the mass of the gas ejected is

A vertical spring is compressed and, when released, applies a force during a 0.25 s time interval to a 17 g frog, which is flung upward due to the applied force from the spring. If the frog attains an upward velocity of 11 m/s after being released from the spring, what average upward force was applied by the spring?

The units of momentum are

Two ice skaters are at rest and facing each other. One skater weighs 140 lbs and the other skater weighs 180 lbs. The skaters "push off" of each other. The 140 lb skater then moves away at 5.00 m/s to the EAST. What is the velocity of the 180 lb skater?

A 90.0 kg person is sitting in a 100 kg boat, which is floating at rest on a lake. In the boat is a stone with a mass of 5.00 kg. The person throws the stone at 4.00 m/s horizontally in the NORTH direction. The kinetic energy of the boat and person after throwing the stone is

A 5.00 kg ball is moving at 4.0 m/s to the right and a 6.00 kg ball is moving at 3.00 m/s to the left. The total momentum of the system is

Two objects collide and stick together. Which of the following is false?

A 3.00 kg mass is located at x = 2.0 cm and y = 0.0 cm. A 3.00 kg mass is located at x = 0.0 cm and y = 2.0 cm. A 4.00 kg mass is located at x = 3.0 cm and y = −3.0 cm. Where is the location of the center of mass?

A 4.00 kg ball is moving at 4.00 m/s to the EAST and a 6.00 kg ball is moving at 3.00 m/s to the NORTH. The total momentum of the system is

A 4.0 kg ball is traveling at 3.0 m/s and strikes a wall. The ball bounces off the wall with a velocity of 4.0 m/s in the opposite direction. If the ball is in contact with the wall for 0.10 seconds, then the magnitude of the average force on the ball during contact is

If a 5.00 kg mass is moving EAST at 10.0 m/s and a 15.0 kg mass is moving WEST at 10 m/s, what is the velocity of the center of mass of the pair?