a 0.772 kg glass jar falls off a shelf and reaches the ground with 11.2 j of ke. how high was the shelf…

a 0.772 kg glass jar falls off a shelf and reaches the ground with 11.2 j of ke. how high was the shelf? (unit = m)

a 0.772 kg glass jar falls off a shelf and reaches the ground with 11.2 j of ke. how high was the shelf? (unit = m)

Answer

Explanation:

Step1: Apply energy - conservation

The potential energy at the shelf $PE = mgh$ is converted entirely into kinetic energy $KE$ at the ground. So $KE=PE = mgh$.

Step2: Solve for height $h$

We can re - arrange the formula $KE = mgh$ to $h=\frac{KE}{mg}$. Given $m = 0.772$ kg, $KE=11.2$ J and $g = 9.8$ m/s². $h=\frac{11.2}{0.772\times9.8}$ $h=\frac{11.2}{7.5656}\approx1.48$ m

Answer:

1.48 m