Question

Calculate the k.e. of a:
a. 1 kg trolley travelling at 2 m/s,
b. a 2 g (0.002 kg) bullet travelling at 400 m/s,
c. a 500 kg car travelling at 72 km/h.

how do i do the working out?

Answer 1

Explanation:

$k.e = \frac{1}{2} m {v}^{2}$

a)

$k.e = \frac{1}{2} \times 1 \times {2}^{2} \\ = 2 \: joules$

b)

$k.e = \frac{1}{2} \times 0.002 \times {400}^{2} \\ = 160 \: joules$

c) 1 km/h = 0.277778 m/s

72 km/h = 20 m/s

$k.e = \frac{1}{2} \times 500 \times {20}^{2} \\ k.e = 100000 \: joules$