a student pushes a 25kg box on a frictionless surface with a

Solution

a) let mass be m =25 kg Force applied = 25N

so work done by force = f.x = 25*12 = 300 J

b) work done = change in kinetic energy

300 = 1/2 * m*v^2 -0

so v = (300*2/25)^1/2 =4.90 m/s

c) velocity , v\' = 2.45

1/2m\' v\'^2 = 300

so m\' = 300*2/2.45*2.45 = 99.95 Kg