Science 9
Force, Motion & Energy
Summative Test 2
Multiple Choice: Identify the choice that best completes the statement or answers the question. Write the letter
only.
1. When does the net force on an object increase?
a. When Δp decreases b. When Δt increases c. When Δt decreases
2. In the equation Δp = m(vf − vi), which quantity is considered to be constant?
a. Initial velocity b. Final velocity c. Mass d.Momentum
3. For how long should a force of 50N50N be applied to change the momentum of an object
by 12kg⋅m/s12kg⋅m/s?
a. 0.24s0.24s b. 4.15s4.15s c. 62s62s d. 600s600s
4. Give an example of an isolated system.
a. A cyclist moving along a rough road c. A baseball player hitting a home run
b. A figure skater gliding in a straight line on an ice rink d. A man drawing water from a well
5. In which type of collision is kinetic energy conserved?
a. Elastic b. Inelastic
6 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 conserved
b. Inelastic collision, because internal kinetic energy is not conserved
c. Elastic collision, because internal kinetic energy is not conserved
d. Inelastic collision, because internal kinetic energy is conserved
7. Two objects having equal masses and velocities collide with each other and come to a rest. Is
momentum conserved in this case?
a. Yes b. No
8. Why would a system have less energy than it originally started with?
a. The energy was lost as heat.
b. The energy was destroyed.
c. More energy was created at the beginning than at the end.
d. The temperature was too low to create heat.
e. There was a miscalculation in the conversion of energy.
9. Which best describes potential energy?
a. Energy of motion b. Energy as heat c. Stored energy d. energy wasted
10. What does the law of conservation of energy state?
a. That potential energy is always equal to kinetic energy
b. That potential energy is always converted to kinetic energy
c. That there is always some energy lost as heat
d. That for any system the total amount of energy remains the same
