If the body in Ex. (28) is moving at 100 m/s on the earth's surfarce, what will be its (i) kinetic energy (ii) total energy ?

Explanation

Data : `m=20kg, v=100m//s`
(i) The kinetic energy of the body
`=(1)/(2)mv^(2)=(1)/(2)xx20kgxx(100m//s)^(2)=10^(6)J.`
(ii) The total energy of the body = kinetic energy + potential energy `=10^(5)J+(-1.2555xx10^(9)J)`
`=(1-12544)xx10^(5)J=-12543xx10^(5)J` ltbr `=-1.2543xx10^(9)J.`