1. A runner at the start of a race generates 302 W of power as he accelerates to 6 m/s . If the runner has a mass of 75 kg, how long did it take him to reach that speed?

2. Give an example of an isolated system

a) A figure skater gliding in a straight line on an ice rink

b) A cyclist moving along a rough road

c) A man drawing water from a well

d) A baseball player hitting a home run

3. For how long should a force of 65 N be applied to an object of mass 46 kg to change its speed from 11 m/s to 36 m/s?

4. Two objects having equal masses and velocities collide with each other and come to a rest. What type of a collision is this and why?

a) Elastic collision, because internal kinetic energy is not conserved

b) Inelastic collision, because internal kinetic energy is not conserved

c) Inelastic collision, because internal kinetic energy is conserved

d) Elastic collision, because internal kinetic energy is conserved

5. Which statement best describes the PE-KE transformations for a javelin, starting from the instant the javelin leaves the thrower's hand until it hits the ground.

a) Initial PE is transformed to KE until the javelin reaches the high point of its arc. On the way back down, KE is transformed into PE. At every point in the flight, mechanical energy is being transformed into heat energy.

b) Initial KE is transformed to PE until the javelin reaches the high point of its arc. On the way back down, there is no transformation of mechanical energy. At every point in the flight, mechanical energy is being transformed into heat energy.

c) Initial PE is transformed to KE until the javelin reaches the high point of its arc. On the way back down, there is no transformation of mechanical energy. At every point in the flight, mechanical energy is being transformed into heat energy.

d) Initial KE is transformed to PE until the javelin reaches the high point of its arc. On the way back down, PE is transformed into KE. At every point in the flight, mechanical energy is being transformed into heat energy.