Question

A 53.4 kg ice skater is at rest when she throws a 0.135 kg snowball east at 15.8 m/s. What is her velocity afterwards?

Answer 1

Answer:

Her velocity afterwards is 0.04 m/s to the west.

Explanation:

Using the conservation of momentum, we have that:

m1u1 + m2u2 = m1v1 + m2v2

Where m is the mass, u is the inicial velocity and v is the final velocity.

The inicial momentum is zero, because the ice skater and the snowball are at rest (u1 = 0 and u2 = 0)

The mass of the snowball is m1 = 0.135 kg and the final velocity is v1 = 15.8 m/s, so the momentum of the snowball is:

m1 * v1 = 0.135 * 15.8 = 2.133 kg*m/s

So from the conservation of momentum, we have that:

0 = 2.133 + m2v2

m2v2 = -2.133

The mass of the ice skater is m2 = 53.4 kg, then we have that:

53.4 * v2 = -2.133

v2 = -2.133 / 53.4 = -0.0399 m/s

Her velocity afterwards is 0.04 m/s to the west.