- #1
jmlibunao
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Homework Statement
A light elastic string has a natural length 1 m. One end of the string is attached to the fixed point O and a particle P of mass 4 kg is suspended from the other end of the string. When hanging in equilibrium, P is 1.2 m below O.
#1 Find the modulus of elasticity of the string.
When P is hanging in equilibrium, it is hit from below by a particle Q, of mass 2 kg, which is traveling vertically upwards. Immediately after the impact, P moves vertically upwards with a velocity u m/s. When the string is just taut, P is still moving vertically upwards with a velocity of √10 m/s.
#2 Find the value of u.
Given that Q is moving with a velocity of 4√3 m/s upwards before it hits P,
#3 show that it is momentarily at rest just after impact.
#4 Find the position of the lowest point, with respect to the equilibrium point, reached by P
in the subsequent motion.
Homework Equations
Young's modulus of elasticity (λ)
λ = (F/A)/(ΔL/Lo)
F - force
A - cross sectional area
ΔL - change in length
Lo - original length
g = 10 m/s^2
I'm also guessing you're going to be using the formulas for Conservation of Energy, Ki + Pi = Kf + Pf, right?
I'm not so sure what other equations can be used
The Attempt at a Solution
So the cross sectional area, A, was not given in the problem. I just assigned a variable A for it so my λ = [(4 kg)(10 m/s^2)/A] / [(0.2)/(1)] = 200A
Sadly this is what I can do for now. Still thinking about the rest. Can anyone help?
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