Please show all work and formulas used. 1) A canoe crosses a 50m wide river in 3

Question

Please show all work and formulas used.

1) A canoe crosses a 50m wide river in 35s, arriving on the spot directly opposite where it started. The river flows at a speed of 0.4m/s, so the velocity of the canoe with respect to the water must point upstream. At what angle must the canoe be pointed upstream?

2) A soccer player kicks a stationary ball of mass 0.43kg. The ball is in contact with her foot for 0.07m, and it has a speed of 20m/s as it leaves the player's foot. How much force does the player exert on the ball?

3) A 70kg ice hockey goalie, originally at rest, catches a 0.150kg hockey puck slapped at him at a velocity of 35.0m/s.  Suppose the goalie and the ice puck have an inelastic collision.  What would their final velocity be in this case?

Explanation / Answer

1) to v across = 50/35

v up is 0.4

so tan theta = 0.4/(50/35)

theta = arctan(0.4/(50/35))=15.64 degrees

Number 2)

Is the .07 really m? I will solve it for m here, and for sec below. Check which one is correct...

For .07m

W = F d

1/2 mv^2 = F d

F = 0.5*0.43*20^2/0.07=1229 N

If .07 is supposed to be seconds, the force changes to 123 N

no.(3)

p initial = p final

0.15*35 = (0.15+70)*v

v=0.0748 m/s

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