Which statement about the physical change of liquid water boiling into steam is true?
a. the heat added represents an energy change
b. the action cannot be reversed.
c. the steam cannot conserve mass
d. the weight lost represents a mass change

Which of the following is a homogenous mixture? o a. a toy box filled with toys o b. blood o c. trail mix o d. spaghetti and meatballs submit

Acombination reaction is when two or more combine to form one product. a decomposition reaction is when a substance breaks down into two or more simpler substances in a chemical reaction.

As you are trying to move a heavy box of mass m, you realize that it is too heavy for you to lift by yourself. there is no one around to , so you attach an ideal pulley to the box and a massless rope to the ceiling, which you wrap around the pulley. you pull up on the rope to lift the box. use g for the magnitude of the acceleration due to gravity and neglect friction forces. once you have pulled hard enough to start the box moving upward, what is the magnitude f of the upward force you must apply to the rope to start raising the box with constant velocity? express the magnitude of the force in terms of m, the mass of the box.