A block moving horizontally on a smooth surface with a speed of 40 m s - 1 splits into two equal parts. If one of the parts moves at 60 m s - 1 in the same direction, then the fractional change in the kinetic energy will be x : 4 where x = ________.

Step-by-step solution

2 m × 40 = 60 × m + m v V = 20   m / s Now Δ K E = K E f - K E i = 1 2   m × ( 20 ) 2 + 1 2   m × ( 60 ) 2 - 1 2 2   m × ( 40 ) 2 Δ K E = 1 2   m ( 800 ) ⇒ K E i = 1 2 2   m × ( 40 ) 2 = 1 2   m × 3200 Fractional change = Δ K E K E i = 1 4