Question

A hockey puck has a mass of 210 g. If the hockey puck has 73 J of kinetic energy, what is its speed?

Answer 1

A hockey puck has a mass of 210 g. If the hockey puck has 73 J of kinetic energy, what is its speed?

Solution.

$$m = 210g = 0.210kg, E_k = 73J;$$ $$v - ?$$

The kinetic energy:

$$E_k = \frac{mv^2}{2};$$ $$v = \sqrt{\frac{2E_k}{m}}.$$ $$v = \sqrt{\frac{2 \cdot 73}{0.210}} = 23.4 \left(\frac{m}{s}\right).$$

Answer: $v = 23.4 \frac{m}{s}$.