You are standing on a large sheet of frictionless ice and ho

You are standing on a large sheet of frictionless ice and holding a large rock. In order to get off the ice, you throw the rock so it has velocity 12.0 m/s relative to the earth at an angle of 35.0 above the horizontal. Your mass is 70.0 kg and the rock’s mass is 4.50 kg .

What is your speed after you throw the rock?

Solution

use the law of conservation of linear momentum to find the velocity.
              P(rock)x + P(man)x = 0
           4.5 * 12cos35 - 70 * v = 0
thus, the velocity is, v = 0.63 m/s