A body of mass 60 kg has the momentum of 3000 kgms-1.
Calculate:
(i) the kinetic energy and
(ii) the speed of the body.
Given,
Mass = 60 kg
Momentum = 3000 kgm / s
(i)
Kinetic Energy=momentum22×mass⇒KE=300022×60⇒KE=3000×3000120⇒KE=75000 J=7.5×104 J\text{Kinetic Energy} = \dfrac{\text{momentum}^2}{2 \times \text{mass}} \\[0.5em] \Rightarrow \text{KE} = \dfrac{3000^2}{2 \times 60} \\[0.5em] \Rightarrow \text{KE} = \dfrac{3000 \times 3000}{120} \\[0.5em] \Rightarrow \text{KE} = 75000\text{ J} = 7.5 × 10^4\text{ J}Kinetic Energy=2×massmomentum2⇒KE=2×6030002⇒KE=1203000×3000⇒KE=75000 J=7.5×104 J\
(ii)
Momentum=Mass×Velocity⇒Velocity=MomentumMass⇒Velocity=300060⇒Velocity=50 ms−1\text{Momentum} = \text{Mass} \times \text{Velocity} \\[0.5em] \Rightarrow \text{Velocity} = \dfrac{\text{Momentum}}{\text{Mass}} \\[0.5em] \Rightarrow \text{Velocity} = \dfrac{3000}{60} \\[0.5em] \Rightarrow \text{Velocity} = 50\text{ ms}^{-1}Momentum=Mass×Velocity⇒Velocity=MassMomentum⇒Velocity=603000⇒Velocity=50 ms−1
