Quantity of heat
Answers are for parents and teachers.
1
Q (J) to heat 0.2 kg of copper (c = 390 J/(kg·K)) from 20 °C to 120 °C?
7800
2
How many joules does 4 kg of water give up cooling from 50 °C to 30 °C? (c = 4200)
336000
3
1 kg of water at 0 °C is added to 3 kg at 80 °C. Final temperature (°C)?
60
4
A copper body (c = 390 J/(kg·K)) falls from a height of 39 m. If half the energy released on impact heats the body, by how much does it warm? (g = 10 m/s²)
Δt = 0.5·gh/c = 0.5·10·39/390 = 0.5 K
5
In summer sand heats up faster than water during the day. Why?
Sand’s specific heat capacity is much smaller than water’s.