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miyayeah
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Homework Statement
The question is as follows: A 50kg ice skater is gliding along the ice, heading due north at 4.0m/s. The ice has a small coefficient of static friction, to prevent the skater from slipping sideways, but kinetic friction =0. Suddenly, a wind from the northeast exerts a force of 4N on the skater. Use work and energy to find the skater's speed after gliding 100m in this wind.
Homework Equations
W= F ⋅ d
W= ΔKE = 1/2 mvf2-1/2 mvi2
The Attempt at a Solution
W= F ⋅ d = (sin45)(4N)(100m) = 282.842712 J
In this step I assumed the angle to be 45 degrees because we are trying to find the y component of the force. (Since there is no movement sideways and speed is not affected by the sideway movement)
I used the above value of work in the next step. I rearranged the formula below to get final velocity.
W= ΔKE = 1/2 mvf2-1/2 mvi2
vf= √[(2W+mvi2)/m]
Plugging in the values from the question gave me 5.2 m/s. The correct answer was 2.2m/s.
Any help would be much appreciated!