Question

The heat Q required to raise the temperature of water varies jointly as the mass m of the water and the amount of temperature change T, and Q=20930 joules (J) when m=1kg and T=5 degrees C. Find m when Q=8372 J and T=10 degrees C

Answer 1

m = 0.2 kg.

Explanation:

Joint variation:

Q = kmT where k is a constant.

Subsituting the given values:

20930 = k*1*5

k = 20930 / 5 = 4186.

So the relation is:

Q = 4186mT

When Q = 8372 and T = 10:

8372 = 4186 * m * 10

m = 8372 / (4186*10)

m = 0.2 kg.