A river has a current of 5 m/s. A boat tries to head directly across at 4 m/s. When the boat reaches the other side it is 30m downstream.

How wide is the river ?

2 answers

how long did it take to get across?
30=5*time

how wide is the river?
W=4t
A 80KG hockey player has a coefficient of friction u=0.08 between her skates and ice. What is the force of friction on the player?

0.08(80 x 9.8)
=62.7N

If the hockey player is coasting, what is the net force?