Question

A body of mass $1kg$ is thrown with a velocity of $10{ms}^{-1}$ at an angle of ${60}^{\circ }$ with the horizontal. Its momentum at the highest point is:

• A. $2kg{ms}^{-1}$
• B. $3kg{ms}^{-1}$
• C. $4kg{ms}^{-1}$
• D. $5kg{ms}^{-1}$

Answer 1

The correct option is D $5kg{ms}^{-1}$

At the highest point, its velocity in the upward direction is zero but its velocity in the horizontal direction remains constant at every instant. Hence , only the horizontal component of velocity is responsible for the momentum of the body at the highest point.

Velocity of the body $v=10$ $m{s}^{-1}$

Velocity component of the body in the horizontal direction $v_H=vcos{60}^o=10\times 0.5=5$ $m{s}^{-1}$

$\therefore$ Momentum $P=m{v}_H=1\times 5=5$ $kg$ $m{s}^{-1}$