- #1
RayanLhindi
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1. Homework Statement
m = 4.00 kg
theta = 30
v = 1 m/s
compression of the spring by the block , x = 0.3 m
d = 5 m
Homework Equations
rule : Fk = μ k * N
i must find Fk first to find μ k using conservation energy, [/B]
The Attempt at a Solution
First find N,
N = m x g x cos theta
N = 4 * 9.81 * cos30 = 33.98N
then we find the force to find the spring constant
F = ma
F = 4 * 9.81 = 39.24N
KE = 0.5 mv^2
KE = 0.5 * 39.24 * 1^2 = 19.62J
PE = 0.5 kx^2 => 0.5 Fx
PE = KE
0.5 Fx = 0.5 mv^2
x = v^2 / a = 1^2 / 9.81 = 0.101m
K = f/x = 392.4
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Here i am confused, our professor told us to use mechanical energy and conservation energy to find Fk ,
and the rules is
delta E = delta E mechanics + delta E thermo + delta E internal
K2 + U2 = K1 + U1 The question is long and very tricky, i solve what i can, and i not sure about it actually, if you can help me i will be very thankful.