Q. A ball is thrown up at an angle with the horizontal. Then the total change of momentum by the instant it returns to ground is
A) Acceleration due to gravity $\times$ total time of flight
B) Weight of the ball $\times \ $ half the time of flight
C) Weight of the ball $\times \ $ total time of flight
D) Weight of the ball $\times \ $ horizontal range
Explanation
(c) Change in momentum of the ball $= mv\sin\theta - ( - mv\sin\theta)$
$= 2mv\sin\theta = 2mgv\frac{\sin\theta}{g} = mg \times \frac{2v\sin\theta}{g}$
$= \ $weight of the ball $\times$ total time of flight
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.