Question : A body of mass 10 kg is moving with a constant velocity of 10 m/s. When a constant force acts for 4 seconds on it, it moves with a velocity 2 m/s in the opposite direction. The acceleration produced in it is
(a) 3 m/s2
(b) -3 m/s2
(c) 0.3 m/s2
(d) -0.3 m/s2
Answer : The correct option is (b)
Solution :
v = u + at
-2 = 10 + a (4)
a = -3 m/s2