How much work does it take to raise a 7 kg  weight 9 m ?

Dec 23, 2015

$- 630$ $J$, considering acceleration due to gravity = $10$ $m$/${s}^{2}$

Explanation:

$\text{Work done = Force x Displacement}$ x $\cos \theta$
i.e. $W = F . s$$\cos \theta$

Here force acts opposite in the direction of displacement therefore $\cos \left({180}^{\circ}\right)$ = $- 1$

Substituting $F = m g$ we get $70$ $k g m$/$s$, $s$ = $9$ $m$
We get
$7$ x $10$ x $9$ x $\left(- 1\right)$ = $- 630$ $J$