Question:
An object of mass $2 \mathrm{~kg}$ is sliding with a constant velocity of $4 \mathrm{~m} \mathrm{~s}^{-1}$ on a frictionless horizontal table. The force required to keep the object moving with the same velocity is
(a) $32 \mathrm{~N}$
(b) $0 \mathrm{~N}$
(c) $2 \mathrm{~N}$
(d) $8 \mathrm{~N}$.
Solution:
(b) Explanation : No force is needed to keep the object moving with constant velocity.