A ball of mass is to be thrown vertically upwards so that it reaches a height of…

PHYSICS · Multi-part · CBSE · Physics · Work, Energy and Power · Work, Energy and Power

Problem

A ball of mass

2\,\text{kg}

is to be thrown vertically upwards so that it reaches a height of

30\,\text{m}

above the point of projection. (i) Calculate the minimum kinetic energy that must be provided to the ball at the instant of projection. Take

g = 9.8\,\text{m\,s}^{-2}

. (ii) Determine the speed with which the ball must be thrown. (iii) When the ball is

20\,\text{m}

above the point of projection on its way up, find its kinetic energy and speed.