Glass has a specific heat of 0.84 J/g·°

c. Copper has a specific heat of 0.39 J/kg·°

c. Which material takes more energy to warm up?

The higher the specific heat capacity level, the more energy it requires to warm it up by 1°C.

Since the unit for the given numbers are different, simply multiply 0.84 by 1000 so that we can know the specific heat capacity of glass is 840 J/kg·°

Comparing both numbers, the value for glass is larger.

Therefore, glass requires more energy to warm up.