# If a boat and its riders have a mass of 1400 kg and the boat drifts in at 1.3 m, show much work...

## Question:

If a boat and its riders have a mass of 1400 kg and the boat drifts in at 1.3 m, show much work does Sam do to stop it?

## Kinetic Energy:

Suppose a rabbit of mass (m) is moving on the ground and it is observed that it is running with a speed (v). In this situation, the kinetic energy that the rabbit has can be given as,

{eq}K = \frac{1}{2}mv^{2}. {/eq}

Given data:

• Mass of the combined boat-rider system, {eq}m = 1400 \ kg {/eq}

Here, 1.3 will be the speed of the boat-rider sytem.

Thus, {eq}v = 1.3 \ m/s {/eq}

In order to stop the boat, an equal amount of work to that of the kinetic energy of the boat-rider system is needed.

Thus,

{eq}\begin{align*} W &= \frac{1}{2}mv^{2}\\ W &= \frac{1}{2} \times 1400 \times (1.3)^{2}\\ W &= 1183 \ J.\\ \end{align*} {/eq}

Kinetic Energy: Examples & Definition

from General Studies Science: Help & Review

Chapter 4 / Lesson 14
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