Answer:
the expression is ΔT = v²/(4*c)
Step-by-step explanation:
the kinetic energy K of the bullet is given by
K=1/2*m*v²
where m= mass , v= velocity
the heat Q absorbed by the bullet is given by
Q = m * c * ( T final - T initial ) , where c= specific heat of lead, T initial = initial temperature, T final = final temperature
then
thermal energy = kinetic energy converted into thermal energy
Q = K - 1/2* K = 1/2*K
replacing values
m * c * ( T final - T initial ) = 1/2* 1/2*m*v² = 1/4*m*v²
the increase in temperature ΔT = ( T final - T initial ) , then
ΔT = ( T final - T initial ) = 1/4*m*v² /(m * c ) = v²/(4*c)
ΔT = v²/(4*c)