Question

A ball has a mass of 0.5kg. Dropped from a cliff top, the ball strikes the sea below at a velocity of 10m/sec.

a. What is the kinetic energy of the ball as it is about to strike the sea?

b. What was its potential energy before it was dropped?

c. From what height was the ball dropped?

d. A stone of mass 1 kg also strkes the sea at 10m/sec. Repeat stages a, b and c above to find the height from which the stone was dropped?


please please answer this​

Answer 1

$1. \:kinetic \: energy \: of \: a \: system \: \frac{1}{2} m {v}^{2} \\ so \\ \frac{1}{2 } \times 0.5 \times {10}^{2} \: kg \: m \: {sec}^{ - 1} \\ \\ \\ 2. \: potential \: energy \: is \: 0 \: before \: dropping\: \\because \: hight = 0 \\ 3. \:we \: know \: energy \: remains \: constat \: in \: the \: whole \: system \: \\ hence \: \: \: \: \: mgh = \frac{1}{2} m {v}^{2} \\ h = 25 \div 10 \\ h = 2.5$