Physics Questions

Question

A(n) 8.6-kg copper block is given an initial speed of 4.4 m/s on a rough horizontal surface. Because of friction, the block finally comes to rest.

(a) If the block absorbs 85% of its initial kinetic energy as internal energy, calculate its increase in temperature.

Answer 1

Set 85% of the initial kinetic energy of the block equal to the rise in thermal energy of the block.

c = specific heat of copper [look it up in units of J/(kg°C)]

m = mass of copper block (given)

v = initial speed of block (given)

ΔT = temperature increase = ?

0.85(mv²/2) = mcΔT ⇒

ΔT = 0.85 v² / (2c)

Plug in the numbers and finish from here. Be careful with units,