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hyemal.zephyr
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Homework Statement
A block of ice with mass 2.0 kg slides 0.90 m down an inclined plane that slopes downward at an angle of 27° below the horizontal. If the block of ice starts from rest, what is its final speed? Friction can be neglected.
m = 2.0 kg
s = 0.90 m
θ = 27°
Homework Equations
W = Fs
W = ΔKE
ΔKE = 0.5m(vf2 - vi2)
The Attempt at a Solution
Using the equations given, I began with the following:
Fs = 0.5m(vf2 - vi2)
Then, because the ice is on a slope, I calculated the force acting on the block:
F = mgcosθ
F = (2.0 kg)(9.81 m/s2)cos(27°)
F = 17.48 N
Plugging all of the variables into the equation, now:
(17.48 N)(0.90 m) = 0.5(2.0 kg)(vf2 - (0 m/s)2)
vf = 3.97 m/s
Apparently, though, this is incorrect. I'm not sure why.
As a side note, I know how to solve the problem using kinematics, but this topic is introducing work, so we have to solve the problem as such.