The bullet/block collision, the bullet initial energy is 1/2 m v^2
The energy converts to heat, mc*deltatemp
So the question is, what is the specific heat of the lead/wood combination. Well, you can learn something here. Do them separately
1/2 massbullet*v^2=masswood*cwood*deltaT + masslead*clead*deltaT
http://www.engineeringtoolbox.com/specific-heat-solids-d_154.html
http://www.sciencebyjones.com/specific_heat1.htm
solve for velocity. What is interesting, is where most of the energy went: the lead, or the wood.
A 15 g lead bullet is tested by firing it into a fixed block of wood with a mass of
1.05 kg. The block and the embedded bullet together absorb all the heat generated. After
thermal equilibrium has been reached, the system has a change in temperature
measured as 0.020 oC. Estimate the entering speed of the bullet.
(Hint: Use the fact that energy is conserved)
1 answer
2 answers