Question

1. Which of the following statements are true?

I. If a car is traveling eastward and slowing down its acceleration is westward.

II. When a ball is tossed straight up, at the highest point of its path, the velocity is zero but the acceleration is non-zero.

III. The average speed of an object is always equal to the magnitude of its average velocity

A.I and II

B.Only III

C.Only I

D.Only II

E.II and III

2.A ball rolls off the edge of a table at the same time another ball drops vertically from the same table. The ball to hit the floor first is the

A.dropped ball.

B.rolling ball.

C.both hit at the same time

3.An archer shoots an arrow. Consider the action force to be the bowstring against the arrow. The reaction to this force is the

A.combined weight of the arrow and bowstring.

B.grip of the archer's hand on the bow.

C.arrow's push against the bowstring.

D.friction of the ground against the archer's feet.

4.Energy is conserved means that

A.The Kinetic energy of the system is constant

B.The sum of the potential and kinetic energy of the system is constant

C.The potential energy of the system is constant

D.All of the above

5.The net impulse on an object is equal to

A.velocity multiplied by time.

B.its change in momentum.

C.momentum.

D.force multiplied by the distance it acts.

Answer 1

1. if a moving car is slowing down that means the acceleration of car will be opposite to the velocity of car so it's true that if a car traveling eastward and slowing down it's acceleration is westward, True

ll. when a Ball is tossed straight up at the highest point of its path the velocity become zero because ball changes its direction of velocity so velocity will be zero at that moment and acceleration due to gravity is always towards downward throughout the motion so acceleration is non zero,. True

III. Average speed is defined with the help of actual path but average velocity is defined with the help of displacement of final and initial point so these are not equal, False

Option A, l and ll are true

2. both will hit at the same time because to hit the floor we have to consider vertical velocity only and vertical velocity is zero in both case initially

Option C

3. the action force to be the bowstring against the arrow then reaction force will be arrow's push against the bowstring, option c

4. energy is conserved means total energy of a system is conserved that is sum of potential energy and kinetic energy of the system is constant, option B

5. the net impulse on an object is equal to it's change in moment, option B