- #1
abram
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Homework Statement
I seem to have a fundamental misunderstanding of the kinematic principles in this question.
A constant force of 8.0N is exerted for 4.0s on a 16-kg object initially at rest. What will the change in speed of this object be?
Homework Equations
F = ma
Δx = v0t + 1/2 at2
Δv = v0 +at
Δv = Δx/Δt
Δv = v0 + aΔt
The Attempt at a Solution
F = ma
thus
a = (8.0N) / (16.0 kg) = .5 m/s^2
then
Δx = (0 m/s)(4 s) + 1/2(.5 m/s^2)(4 s)^2 = 4 m
if
Δv = Δx/Δt
then
Δv = (4 m) / (4 s) = 1 m/s
but using Δv = aΔt
Δv = (.5 m/s^2)(4 s) = 2 m/s
I don't understand why I would have two conflicting answers there. Just curious if anyone might have some insight on why that would be. Thanks!