You have 4.9 g of an unknown substance. to identify the substance, you decide to measure its specific heat and find that it requires 668.85 j of heat to increase the temperature of your sample by 39 k. what might this substance be?

Asap and show ! a 14 kg rock starting from rest free falls through a distance of 5.0 m with no air resistance. find the momentum change of the rock caused by its fall and the resulting change in the magnitude of earths velocity. earth mass is 6.0 * 10^24 kg. show your work assuming the rock earth system is closed.