Solving for Kinetic Energy Lost in Spring Gun

AI Thread Summary
The discussion revolves around calculating the fraction of kinetic energy stored in a spring when a ball is shot into a spring gun. A ball of mass 56 g is shot at 20 m/s and sticks in the barrel of a 222 g spring gun, which is initially at rest. The final velocity after the collision is calculated to be -4.03 m/s using the conservation of momentum equation. The kinetic energy before the collision is compared to the kinetic energy after the collision to determine how much energy is stored as potential energy in the spring. Participants are trying to clarify how to correctly calculate the fraction of energy stored without encountering division by zero issues.
TS656577
Messages
62
Reaction score
0

Homework Statement


A ball of mass m = 56 g is shot with speed vi = 20 m/s (in the negative direction of an x axis) into the barrel of a spring gun of mass M = 222 g initially at rest on a frictionless surface. The ball sticks in the barrel at the point of maximum compression of the spring. Assume that the increase in thermal energy due to friction between the ball and the barrel is negligible. What fraction of the initial kinetic energy of the ball is stored in the spring?

Homework Equations


m1v1=(m1+m2)v2
K=.5mv^2


The Attempt at a Solution


I found the final velocity to be -4.03 m/s by using m1v1=(m1+m2)v2 and got v2 to be -4.03m/s. From here I am kind of stuck. It means that its stored as potential energy...so U=Ki-Kf and I have Ki as 0 and Kf as 2257.49. Would i take the potential divided by the Kinetic?
 
Physics news on Phys.org
Hi
your on the right tracks
 
but if you take the potential divided by kinetic, you get division by 0
 
still stumped
 
Kindly see the attached pdf. My attempt to solve it, is in it. I'm wondering if my solution is right. My idea is this: At any point of time, the ball may be assumed to be at an incline which is at an angle of θ(kindly see both the pics in the pdf file). The value of θ will continuously change and so will the value of friction. I'm not able to figure out, why my solution is wrong, if it is wrong .
Thread 'Voltmeter readings for this circuit with switches'
TL;DR Summary: I would like to know the voltmeter readings on the two resistors separately in the picture in the following cases , When one of the keys is closed When both of them are opened (Knowing that the battery has negligible internal resistance) My thoughts for the first case , one of them must be 12 volt while the other is 0 The second case we'll I think both voltmeter readings should be 12 volt since they are both parallel to the battery and they involve the key within what the...
Back
Top