A body of mass 5 kg is moving with a momentum of 10 kg-m/s. A force of 0.2 N acts on it in the direction of motion of the body for 10 seconds. The increase in its kinetic energy is :
Answer & explanation
Correct answer: option 1
Initial KE \( = \frac{p^2_1}{2m} = \frac{10*10}{2*5} = 10 \text{ J}\)
Impulse \( = p_2 - p_1 = F*t\)
\(\Rightarrow p_2 - 10 = 0.2 * 10\)
\(\Rightarrow p_2 = 12 \text{ kg m/s}\)
Final KE \( = \frac{p^2_2}{2m} = \frac{12*12}{2*5} = 14.4 \text{ J}\)
\(\Delta KE = 14.4 \text{ J} - 10 \text{ J} = 4.4 \text{ J}\)