Question

b) Two skaters collide and grab on to each other on a frictionless ice. One of them, of mass 80 kg, is moving to the right at 5.0 m/s, while the other of mass 70 kg is moving to the left at 2.0 m/s. What are the magnitude and direction of the two skaters just after they collide

Answer 1

The two skaters move with a speed of 1.73 m/s after the collision in the right direction.

Step-by-step explanation:

Given that,

The mas of skater 1, m₁ = 80 kg

The speed of skater 1, u₁ = 5 m/s (right)

The mass of skater 2, m₂ = 70 kg

The speed of skater 2, u₂ = -2 m/s (left)

Let v is the magnitude of the two skaters just after they collide. They must have a common speed. So, using the conservation of momentum as follows :

`m_1u_1+m_2u_2=(m_1+m_2)v\\\\v=(m_1u_1+m_2u_2)/((m_1+m_2))`

Put all the values,

`v=(80(5)+70(-2))/((80+70))\\\\=1.73m /s`

So, the two skaters move with a speed of 1.73 m/s after the collision in the right direction.