A block of mass 10 kg, moving in x direction with a constant speed of 10 ms–1, is subjected to a retarding force F = 0.1 x J/m during its travel from x = 20 m to 30 m. Its final KE will be :
Answer & explanation
Correct answer: option 4
W = - ∫ F dx
F = 0.1 x J/m
⇒ W = - ∫2030 0.1 x dx
W = - 0.1 \([\frac{x^2}{2}]_20^30\)
W =- 25 J
W = Kf - Ki
Ki = \(\frac{1}{2}(10)(10)^2\)
Kf = 475 J