Solving Projectile Motion Using Energy Video Lessons

Example

# Problem: A 2.8-kg block slides over the smooth, icy hill shown in the figure. The top of the hill is horizontal and 70 m higher than its base.What minimum speed must the block have at the base of the 70-m hill to pass over the pit at the far (righthand) side of that hill?

###### FREE Expert Solution

We'll use the kinematic equation:

$\overline{){\mathbf{∆}}{\mathbf{y}}{\mathbf{=}}{{\mathbf{v}}}_{{\mathbf{0}}}{\mathbf{t}}{\mathbf{-}}\frac{\mathbf{1}}{\mathbf{2}}{\mathbf{g}}{{\mathbf{t}}}^{{\mathbf{2}}}}$

Consider the conservation of energy:

$\overline{){\mathbf{∆}}{\mathbf{U}}{\mathbf{=}}{\mathbf{∆}}{\mathbf{K}}}$

The block is starting from rest, so v= 0

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###### Problem Details

A 2.8-kg block slides over the smooth, icy hill shown in the figure.

The top of the hill is horizontal and 70 m higher than its base.

What minimum speed must the block have at the base of the 70-m hill to pass over the pit at the far (righthand) side of that hill?