Question

A 60 kg student is standing in the train station next to her 10 kg suitcase when her train is called. (A) Estimate how much work she does picking up the suitcase. (B) She sprints 2 m, accelerating herself and her suitcase at 0.1 m/s2. How much force does she exert? (C) How much work does she do in this 2 m? (D) She now continues running at constant speed for 10 m to the train. How much work does she do in this 10 m? (E) What is her final kinetic energy as she reaches the train?

Answer 1

Answer

given,

mass of student = 60 Kg

mass of suitcase = 10 Kg

a) Work done by picking of Suitcase is equal to zero

b) acceleration = 0.1 m/s²

   distance = 2 m

Using second law conservation

F = m a

F = 10 x 0.1 = 1 N

c) Work done

  W = F x s

  W = 1 x 2 = 2 J

d) When the are moving with constant speed acceleration is equal to zero

F = m a

F = 10 x 0 = 0 N

W = F x s = 0 x s = 0 J

e)   work done = change in kinetic energy

        K.E = 2 J