Question

A 40 kg child travels in her parents' car, sitting on the back seat, fastened by a seat belt. At a given moment, the car reaches a speed of 20 m/s. At that moment, the child's kinetic energy is equal:

5000 J

8000 J

2600J

9500 J

26000 J

Answer 1

Resposta:

8000 J

Explicação:

The kinect energy can be written as a word equation:

kinect energy = (1/2) . mass . speed²

in symbols:

$K=\frac{1}{2}mv^2$

we have

m = 40 kg

v = 20 m/s

hence

$K=\frac{1}{2}.40.20^2\\ \\K=20^3\\\\K=8000J$