A force acting on a body of mass 5 Kg is (4 i -2 j +3 k ) N . If the body is initially at rest then the magnitude of its velocity at the end of 10 second in m / s will be

Step-by-step solution

Newton's second law gives the acceleration as a = F m = 4 i - 2 j + 3 k 5 = (0.8 i - 0.4 j + 0.6 k ) m/s 2 . Starting from rest, the velocity after 10 s is v = a t = (0.8 i - 0.4 j + 0.6 k ) 10 = (8 i - 4 j + 6 k ) m/s. The magnitude is | v | = 8^2 + (-4)^2 + 6^2 = 64 + 16 + 36 = 116 = 2 29 m/s. Answer: B