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lettertwelve
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bullet and pendulum bob...initial speed...help! momentum.
An 7.0 g bullet is fired into a 3.5 kg pendulum bob initially at rest and becomes embedded in it. If the pendulum rises a vertical distance of 8.0 cm, calculate the initial speed of the bullet.
________m/s
well there's many ways to do it, but here's one way:
v=sqrt((1+M/m)*2gh)
i tried it another way too, and got the same answer that i did with the above equation
so first, 7g bullet = .007kg bullet and height of 8cm = .08m
ok so then v=sqrt((1+3.5/.007)*2*9.8*.08) = ~28.03 m/s
now, i tried this TWO WAYS and got the same answer.
but webassign says it's wrong.
why?
Homework Statement
An 7.0 g bullet is fired into a 3.5 kg pendulum bob initially at rest and becomes embedded in it. If the pendulum rises a vertical distance of 8.0 cm, calculate the initial speed of the bullet.
________m/s
Homework Equations
well there's many ways to do it, but here's one way:
v=sqrt((1+M/m)*2gh)
i tried it another way too, and got the same answer that i did with the above equation
The Attempt at a Solution
so first, 7g bullet = .007kg bullet and height of 8cm = .08m
ok so then v=sqrt((1+3.5/.007)*2*9.8*.08) = ~28.03 m/s
now, i tried this TWO WAYS and got the same answer.
but webassign says it's wrong.
why?