Question

Two ice skaters initially at rest, push of each other. If one skater whose mass is 60 kg has a velocity of 2m/s. What is the velocity of other skater whose mass is 40 kg? (Ans: 30m/s in opposite direction)

Answer 1

m 1 =60 kg

v 1 =2 m/s

m 2 =40 kg

v 2=?

p 2 =?

p 1 = mv

p 1= 60 x 2

p 1=120 kg m/s

p 1=p 2

p = mv

120 = 40 x v 2

v 2=120/40

v 2=3 m/s

actually these answer is 3 m/s but in the old text books of the physical science th answer is 30 m/s but thse answer is wrong