A chair is pushed backward with a force of 100 N. The gravitational force of Earth on the chair is 120 N downward, and the floor exerts a force of 120 N upward on the chair.
Draw a free-body diagram showing the forces acting on the chair.

What does the law of conservation of mass state?

An insulated thermos contains 148 g of water at 72.7 ˚c. you put in a 11.7 g ice cube at 0.00 ˚c to form a system of ice + original water. the specific heat of liquid water is 4190 j/kg•k; and the heat of fusion of water is 333 kj/kg. what is the net entropy change of the system from then until the system reaches the final (equilibrium) temperature?

Three resistors are connected in series across a 15-v power supply. if the potential drops across resistors 1 and 2 are 4.1 volts and 3.1 volts, what is the exact potential drop (in volts) across resistor 3?