A lead bullet flying at a speed of 200 m / s pierces the board and splits at a speed of 100 m / s.

A lead bullet flying at a speed of 200 m / s pierces the board and splits at a speed of 100 m / s. how many degrees the bullet was heated if all the work went to heating.

Data: V1 (velocity of the considered lead bullet before contact with the board) = 200 m / s; V2 (speed after breaking through the board) = 100 m / s.

Constants: Cc (specific heat capacity of lead) = 140 J / (kg * K).

To calculate the temperature rise of the considered lead bullet, we will use the equality: ΔEk = A = Q = Cc * m * Δt; 0.5 * m * (V1 ^ 2 – V2 ^ 2) = Cc * m * Δt, whence Δt = 0.5 * (V ^ 12 – V2 ^ 2) / Cc.

Let’s calculate: Δt = 0.5 * (200 ^ 2 – 100 ^ 2) / 140 = 107.14 ºС.

Answer: The bullet temperature increased by 107.14 ºС.