A pinball bangs against a bumper, giving the ball a speed of 52 cm/s. If the ball has a mass of 50.0 g, what is the ball's kinetic energy in joules?

Feb 3, 2016

I found: $K = 6.76 \times {10}^{-} 3 J$

Explanation:

We need first to change into $\frac{m}{s}$ and $k g$ to get:
$52 \frac{c m}{s} = \frac{52}{100} \frac{m}{s} = 0.52 \frac{m}{s}$
and:
$50 g = \frac{50}{1000} k g = 0.05 k g$
Kinrtic Energy will be:
$K = \frac{1}{2} m {v}^{2} = \frac{1}{2} \left(0.05\right) {\left(0.52\right)}^{2} = 6.76 \times {10}^{-} 3 J$

Feb 3, 2016

$6.76 \times {10}^{- 3} j$

Explanation:

we know that,

${E}_{K} = \frac{1}{2} m {v}^{2}$

here,
$m = 50 g m = 0.05 k g$
$v = 52 \frac{c m}{s} = 0.52 \frac{m}{s}$

so,
${E}_{K} = \frac{1}{2} \cdot 0.05 \cdot {\left(0.52\right)}^{2}$
$= 6.76 \times {10}^{- 3} j$