Question

A particle is projected vertically upwards in absence of air resistance with a velocity u from a point O. When it returns to the point of projection:

(1) Its a average velocity is zero

(2) Its displacement is zero

(3) Its average speed is $\frac{u}{2}$

(4) Its average speed is u

• A. 1 and 2 are correct
• B. 1,2 and 3 are correct
• C. only 4 is correct
• D. 3 and 4 are correct

Answer 1

The correct option is B

1,2 and 3 are correct

For a round trip, net displacement and average velocity is zero.

For the round trip, average speed = $v_{avg}=\frac{2h}{2\sqrt{\frac{2h}{g}}}=\frac{\sqrt{2gh}}{2}=\frac{u}{2}$