- A particle of mass 4 kg is moving in a straight horizontal line. There is a constant resistive force of magnitude \(R\) newtons. The speed of the particle is reduced from \(25 \mathrm {~m} \mathrm {~s} ^ { - 1 }\) to rest over a distance of 200 m .
Use the work-energy principle to calculate the value of \(R\).