Solution : –
We have, kinetic energy of bullet is converted into heat = 1/2 mv2
= 1/2 ×18×10–3×(500)2
= 2.25×103 J
= (2.25×103)/(4.184×103) kcal
= 0.538 kcal
Also, mS = mS for bullet + mS for wood
= 18×10–3×0.030 + 1×0.50
And q = K.E.= mS∆T
Therefore, ∆T = K.E./(mS)
= 0.538/(18×10–3×0.030 + 1×0.50)
= 1.08 K
= 1.08° C
Therefore, final temperature = 25.0° C + 10.8° C
= 26.08° C