A 2.00-g lead bullet is shot with a speed of 250 m/s into a wooden wall.Assuming that all of its kinetic energy is absorbed as heat by the bullet,what is the temperature increase of the bullet?

Question

Quizplus · Accepted Answer

We can use the formula for thermal energy: 
Q = mcΔT 
where Q is the thermal energy absorbed, m is the mass of the bullet, c is the specific heat of lead, and ΔT is the temperature increase. 
First, we need to convert the mass of the bullet to kilograms: 
m = 0.002 kg 
The specific heat of lead is 0.128 J/g·°C, but we need to convert to kg·m²/s²·K: 
c = 0.128 J/g·°C × (1 kg/1000 g) × (1 m²/s²/ J) = 1.28 x 10^3 kg/m²·K 
Now we can plug in the values: 
Q = (0.002 kg)(250 m/s)²/2 = 125 J 
125 J = (0.002 kg)(1.28 x 10^3 kg/m²·K)ΔT 
ΔT = 242°C 
Therefore, the temperature increase of the bullet is 242°C, or choice C.

A 200-G Lead Bullet Is Shot with a Speed of 250