16. Which of the following statements is true about centripetal force?
a) It is the force that pulls an object outward from the center of the circle
b) It is the force that pulls an object towards the center of the circle
c) It is the force that opposes the motion of an object in a circle
d) It is the force that causes an object to move in a straight line
17. Which of the following factors affects the centripetal force required for an object to move in a circle?
a) Mass of the object
b) Speed of the object
c) Radius of the circle
d) All of the above
18. Which of the following statements is true about the coefficient of restitution?
a) It is a measure of the roughness of a surface
b) It is a measure of how much kinetic energy is lost during a collision
c) It is a measure of how much potential energy is gained during a collision
d) It is a measure of the elasticity of a collision
19. Which of the following statements is true about the law of conservation of momentum?
a) The total momentum of a system remains constant if no external forces act on it
b) The total momentum of a system increases if external forces act on it
c) The total momentum of a system decreases if external forces act on it
d) The total momentum of a system is always zero
20. Which of the following statements is true about work done by a force?
a) Work done is always positive
b) Work done is always negative
c) Work done is zero if the force and displacement are perpendicular to each other
d) Work done is zero if the force and displacement are in the same direction
