Question

The kinetic energy of an 1800-kg truck is 7.2 × 105 J. What is the speed of the truck?

Answer 1

The kinetic energy of an 1800-kg truck is $7.2 \times 105$ J. What is the speed of the truck?

The kinetic energy of the body equals:

$$T = \frac{m v^{2}}{2}$$

where $m$ - mass of the body, $v$ - speed of the body.

Therefore, speed equals:

$$\frac{2T}{m} = v^{2}$$ $$v = \sqrt{\frac{2T}{m}} = \sqrt{\frac{2 * 7.2 * 10^{5} J}{1800 \, kg}} = 28 \, \frac{m}{s}$$

Answer: $28 \, \frac{m}{s}$