Question

In a projectile motion near the surface of the Earth, magnitude of rate of change of speed over the complete flight

• A. Always remains constant.
• B. First decreases then increases.
• C. First increases then decreases.
• D. Is zero for complete flight

Answer 1

Answer: (B)

First decreases then increases.

Answer 2

g sin θ is the rate of change of speed of the projectile, where θ is the angle velocity vector is making with horizontal at any time. From projection to the maximum of height, θ decreases thus decreasing ‘g sin θ’. After that θ increases, increasing ‘g sin θ’.