JEE Main Physics question
A ship weighing 0.3 × 10⁸ kg-wt is pulled by a force of 0.5 × 10⁵ N through a distance of 3 m. If the ship were originally at rest and water-resistance is negligibly small, then the ship will acquire a speed of
Answer: (A)
Solution
W = Fs = 0.5×10⁵×3 = 1.5×10⁵ J becomes the ship's KE: ½mv² = Fs ⟹ v² = 2Fs/m = (2×1.5×10⁵)/(0.3×10⁸) = 0.01 ⟹ v = 0.1 ms⁻¹.
## 6.2 Energy