Question

body of mass 20 kg is dropped from a height of 100 M find its kinetic and potential energy first first II II II II II

Answer 1

PE = mgh
=20×10×100
=2000joule
KE = 1÷2×mv×v

h= 100m
u=0
g= 10m per sq second
h= ut+ 1÷2× gt×t
100= 1÷2×10×t×t

$\sqrt{20} = t \\ v = u + gt \\ v = 10 \times \sqrt{20} \\ v = 10 \sqrt{20}m \: per \: sec \\ kinetic \: energy \\ = 1 \div 2 \times mv ^{2} \\ 1 \div 2 \times 20 \times 10 \sqrt{20} \times 10 \sqrt{20} \\ 20000joules$