 #1
Deckname
 6
 0
 Homework Statement:

A bullet of mass 20g hits a steel plate at 600m/s and ricochets in the direction of CD at 500m/s. The bullet makes an indentation in the plate of length 50mm with an entering and exiting angle of beta. The angle alpha between the leaving velocity vector and the horizon is 30°
Calculate the average force of resistance the steel plate is providing the bullet with.
Solution: 9.46x10^7 N
 Relevant Equations:
 (1/2)mv^2
I tried getting to the solution by the principle of conservation of energy. What goes in, must go out. If the final velocity, ie. the final kinetic energy is lower than what we started with, that energy difference must've been used to overcome the friction that lasted over some distance L, meaning that the energy spent to overcome the friction is equal to the work done by the friction force F over the distance L. My way of thinking is now that KE(i)KE(f)=F*L. It turns out I'm wrong and I don't really know how else I can attempt to arrive at the correct solution, which is magnitudes above what I keep getting.