Question

Lora (of mass 43.6 kg) is an expert skier. She starts at 3.6 m/s at the top of the lynx run, which is 67 m above the bottom. What is her final kinetic energy at the bottom of the ski run?

Answer 1

Explanation:

As per the law of conservation of energy, the final mechanical energy of Lora is equal to its initial mechanical energy. So, when Lora is at the bottom of ski run then her potential energy will change into kinetic energy.

Hence,   $E_{initial} = \frac{mv_{i}^{2}}{2} + mgh$

              $E_{final} = \frac{mv_{f}^{2}}{2}$

Now, final kinetic energy that will be at the bottom of the ski run is as follows.

Let,          $E_{k} = E_{final}$

            $E_{intial} = E_{final}$

          $E_{k} = \frac{mv_{i}^{2}}{2} + mgh$

                   = $\frac{(43.6 \times (3.6)^{2}}{2} + (43.6 \times 9.81 \times 67)$

                   = 282.53 + 28656.97

                  = 28939.502 J

Thus, we can conclude that her final kinetic energy at the bottom of the ski run is 28939.502 J.