PHY 2053 Midterm: Sum12Exam2Solutions
Document Summary
The free-body diagram for the block is fk. The work done by kinetic friction fw k. Mechanical energy is not conserved since the sled stops moving. W nc r f k cos f k. The force information gives the force constant for the spring. Mechanical energy is conserved as the ball exits the gun. The work done by the engine increases the car"s kinetic energy. The power output by the engine rate of the work done by the engine. The force is found from the impulse-momentum theorem. Since this is a vector equation, we must take components. Since the motion is only along the x-axis, only the x-component is needed. p x. The change in momentum is p x mv fx mv ix. Linear momentum is conserved since the explosion is an internal force. 600 kg m/s p i mv i v1f m1. Since linear momentum is conserved, p i p f vmp.
