A lead pellet flying at a speed of 100 m / s hits the board and gets stuck in it. 52% of the kinetic energy of the pellet

| July 11, 2021 | education

A lead pellet flying at a speed of 100 m / s hits the board and gets stuck in it. 52% of the kinetic energy of the pellet goes to its heating by how many degrees the pellet has heated up, the specific heat capacity of lead is 460 J / (kg * degree Celsius).

V = 100 m / s.

C = 460 J / kg * ° C.

Q = k * EC / 100%.

k = 52%.

Δt -?

The kinetic energy of a bullet Ek is determined by the formula: Ek = m * V ^ 2/2, where m is the mass of the bullet, V is the speed of the bullet.

The amount of heat Q required to heat the bullet is expressed by the formula: Q = C * m * Δt, where C is the specific heat capacity of the material from which the bullet is made, m is the mass of the bullet, Δt is the change in the bullet temperature.

C * m * Δt = k * m * V ^ 2/2 * 100%.

The bullet temperature change Δt will be determined by the formula: Δt = k * V ^ 2 / С * 2 * 100%.

Δt = 52% * (100 m / s) ^ 2/460 J / kg * ° C * 2 * 100% = 5.7 ° C.

Answer: The bullet temperature will increase by Δt = 5.7 ° C.



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