- #1
nahya
- 27
- 0
A rifle bullet of mass m = 2.5 g traveling at vb = 243 m/s collides with and embeds itself in a pendulum of mass M = 237.5 g, initially at rest and suspended vertically with massless strings of length L = 2 m.
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i first converted the masses into kilograms.
i found out that net momentum = 0.6075 kg m/s, for the bullet-pendulum mass of 0.24kb. that means that the pendulum moves at first with v = 2.53125.
now... where do i go from here?
i don't even know the angle at which the bullet-pendulum combination reaches the max height. if i knew, it would be 2*tan(theta).
so i guess the challenge is to find the angle at which the thing goes at its max height...? bleh.. I'm lost
edit:
by the energy equation, i guess...
for M = total mass, 1/2*Mv(f)^2 + Mgy(f) = 1/2*Mv(i)^2 + Mgy(i)
y(i) is zero, so the last term cancels out.
v(f) is zero, so the first term cancels out.
Mgy(f) = 1/2*Mv(i)^2
y(f) = Mv(i)^2 / (2Mg)
i get 0.6538, which is not the answer...
---
i first converted the masses into kilograms.
i found out that net momentum = 0.6075 kg m/s, for the bullet-pendulum mass of 0.24kb. that means that the pendulum moves at first with v = 2.53125.
now... where do i go from here?
i don't even know the angle at which the bullet-pendulum combination reaches the max height. if i knew, it would be 2*tan(theta).
so i guess the challenge is to find the angle at which the thing goes at its max height...? bleh.. I'm lost
edit:
by the energy equation, i guess...
for M = total mass, 1/2*Mv(f)^2 + Mgy(f) = 1/2*Mv(i)^2 + Mgy(i)
y(i) is zero, so the last term cancels out.
v(f) is zero, so the first term cancels out.
Mgy(f) = 1/2*Mv(i)^2
y(f) = Mv(i)^2 / (2Mg)
i get 0.6538, which is not the answer...
Last edited: