WEP A 1kilogram rock is dropped from a cliff 90 meters high. After falling 20 meters, the kinetic energy of the rock is approximately 1. 20] 2. 200} 3. 700} 4. 900} If the speed of a car is doubled, the kinetic energy of the car is 1 . quadrupled 2. quartered 3. doubled 4. halved A constant force is used to keep a block sliding at constant velocity along a rough horizontal track. As the block slides, there could be an increase in its 1. gravitational potential energy, only 2. internal energy, only 3. gravitational potential energy and kinetic energy 4. internal energy and kinetic energy As an object falls freely, the kinetic energy of the object 1. decreases 2. increases 3. remains the same An object weighing 15 newtons is lifted from the ground to a height of 0.22 meter. The increase in the object's gravitational potential energy is approxi mately 1. 310] 2. 32] 3. 3.3] 4 0.34] A 0.5 Okilogram ball is thrown vertically upward with an initial kinetic energy of 25 joules. Ap proximately how high will the ball rise? [Neglect air resistance.] 1. 2.6 m 2. 5.1 m 3. 13 m 4 25 [11 Energy 7. A 45kilogram boy is riding a 15kilogram bicycle with a speed of 8 meters per second. What is the combined kinetic energy of the boy and the bicycle? 1. 240] 2. 480] 3. 1440] 4. 1920] 8. The work done in moving a block across a rough surface and the heat energy gained by the block can both be measured in 1. watts 2. degrees 3. newtons 4. joules Base your answers to questions 9 through 11 on the information below. A 50kilogram child running at 6 meters per second jumps onto a stationary 10kilogram sled. 'Ihe sled is on a level frictionless surface. 9. Calculate the speed of the sled with the child after she jumps onto the sled. [Show all work, including the equation and substitution with units] 10. Calculate the kinetic energy of the sled with the child after she jumps onto the sled. [Show all work, including the equation and substitution with units.] 11. After a short time, the moving sled with the child aboard reaches a rough level surface that exerts a constant frictional force of 54 newtons on the sled. How much work must be done by friction to bring the sled with the child to a stop? WEPEnergy 12. Which graph best represents the relationship between the kinetic energy, KB, and the velocity of an objct ac celerating in a straight line? I.\" I.I.| Z L I 0 Velocity 0 Velocity 0 Velocity 0 Velocity (1} {2) (3} (4) KE Lu K 13. The graph below represents the kinetic energy, gravitational potential energy, and total mechanical energy of a moving block. Energy Vs. Distance Moved Keyr --- Kinetic energyI ---------- Gravitational potential energy Total mechanical energy Distance moved Which best describes the motion of the block? 1. accelerating on a at horizontal surface 2. sliding up a frictionless incline 3. falling freely 4. being lifted at constant velocity Base your answers to questions 14 through 16 on the information and diagram below. 11: 6.0 ml's i": 0.0 We 5- A IUOUkilogram empty cart moving with a speed of 6 meters per second is about to collide with a stationary loaded cart having a total mass of 5000 kilograms, as shown. After the collision, the carts lock and move together. [Assume friction is negligible.] 14. Calculate the speed of the combined carts after the collision. [Show all work, including the equation and substi tution with units.] 15. Calculate the kinetic energy of the combined carts after the collision. [Show all work, including the equation and substitution with units] 16. How does the kinetic energy of the combined carts after the collision compare to the kinetic energy of the carts before the collision