Question

At the center of a 41.0 m diameter circular ice rink, a 61.0 kg skater traveling north at 1.05 m/s collides with and holds onto a 77.0 kg skater who had been heading west at 1.90 m/s. How long (in seconds) will it take them to reach the edge of the rink assuming negligible friction and drag?

Answer 1

use conservation of momentum to find the new momentum.

New momentum: 61*1.05N+77*1.90W

absolute speed: sqrt [(61*1.05)^2 + (77*1.9)^2 ]

then time= distance/speed= 41/2 * 1/speed

Answer 2

I did this and it still says it is incorrect...

Answer 3

I bet you made an error. Do you see anything wrong with the approach, or thinking? Have you checked your work? Post it here, and someone can critique it.

Answer 4

I used the equation m1vf1 + m2vf2 = m1vi1 + m2vi2 and got a vf of 1.52m/s

I then plugged that into the equation t=d/v => t=20.5/1.52 and got 13.5s

Answer 5

Is there some reason you did not do what I told you? What you did is really very wrong. Please look at the solution I outlined. And I see I have an error, where I typed absolute speed, it should read absolute momentum, then a new line
absolute speed= absolute mometnum/total mass I get about 1.1 for the speed (not 1.1).

Answer 6

Yeah I did do it the way you told me at first and got a number that made absolutely no sense but the way you just illustrated makes more sense....thank you