Apuck of mass 0.70 kg approaches a second, identical puck that is stationary on frictionless ice. the initial speed of the moving puck is 6.0 m/s. after the collision, one puck leaves with a speed v1 at 30° to the original line of motion. the second puck leaves with speed v2 at 60°. calculate v1 and v2.

Explanation:

For this problem, we just need to remember conservation of momentum, as there are no external forces in the horizontal direction:

where the suffix i  means initial, and the suffix f means final.

The initial momentum will be:

as the second puck is initially at rest:

Using the unit vector pointing in the original line of motion:

So:

Knowing the magnitude and directions relative to the x axis, we can find Cartesian representation of the vectors using the formula

So, our velocity vectors will be:

We got

So, we got the equations:

and

.

From the last one, we get:

and, for the first one:

so:

and

temp rises, and expansion