A ball of mass $4\ kg$ was thrown in such a way that it traveled $50\ meters$ above the ground. Find the work done?

A) -2880 J

(B) - 1960 J

(C) 1960 J

D) 2880 J

Given: Mass of the ball $m=4\ kg$, Height traveled upward $h=50\ m$, Gravitational acceleration will be negative, as the motion of the ball is against gravity. $g=-9.8\ m/s^2$

To do: To find the work done.

Solution: As the ball is thrown upwards and it travels $50\ m$ above the ground.

Therefore, work done will be equal to the potential energy possessed by the ball at the height of $50\ m$.

So, the work done $W=mgh$

$\Rightarrow\ W=4\ kg\times(-9.8\ m/s^2)\times 50\ m$

Or $W=-1960\ J$    [Here $-ve$ sign indicates that the work done is against gravity]

Therefore, option (B) is correct.

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Updated on: 10-Oct-2022

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