IV.    A person is driving a car slowly forward with a speed of 5 m/s. The driver finds a frog resting on the windshield. The driver tries to get rid of the frog by tapping the glass. The frog jumps vertically upward (relative to the driver and the frog itself). This is being watched by a child sitting at the side of the road. Which of the following is not correct? Assume there is no wind and air resistance.

    A.    The frog will land at the top of the car behind the windshield.
    B.    The path of the frog looks like a parabola to the child.
    C.    To both the driver and the child, the frog always accelerates downward with a magnitude of 9.8 m/s2 when it is in the air.
    D.    To the driver, the frog is instantaneously at rest when it reaches the highest point.
    E.    To the child, the horizontal component of the frog's velocity is always 5m/s.

Ans. A

V.

The locations of a particle is displayed in the above figure. Which of the following statements is not consistent with your observation from t=0s to t=0.9s:

    A.    The total force acting on the particle is not zero.
    B.    The particle is moving with a constant speed.
    C.    The net force acting on the particle is in the same direction as the velocity.
    D.    The velocity of the particle is tangent to the circular path.
    E.    The net force acting on the particle is in the same direction as the acceleration.

Ans. C