Identify each energy exchange as primarily heat or work and determine whether the sign of ΔE is positive or negative for the system. Identify each energy exchange as primarily heat or work. a. A rolling billiard ball collides with another billiard ball. The first billiard ball (defined as the system) stops rolling after the collision. b. A book falls to the floor. (The book is the system). c. A father pushes his daughter on a swing. (The daughter and the swing are the system). Identify each energy exchange as primarily heat or work.

Video transcript

Hi everyone here. We need to classify the following energy exchange processes as work where he transferred. We need to identify the sign of entropy change. So we have an ice cream cone melting when left out of a freezer. We're gonna have an ice cream cone as a system. This is going to be a heat transfer. The ice cream absorbs heat from the surroundings to melt. So the energy is gonna transfer in the form of heat in the sign of delta eat. It's positive when the ice cream melt, its temperature increases. So the sign is going to be positive for B. A. Car were in another car, the car that we're in, we can consider a system is going to stop after the collision. This is gonna be a work transfer since the car is pushing the transfer is classified as work. Got to eat. It's gonna be negative since the car stops and transfers connect energy to the car in front of it. The sun is gonna be negative, precedes the temperature of the room increases when the refrigerator is left running inside it for a few hours. I'm going to consider the contents inside the refrigerator as a system. There's going to be a heat transfer. The temperature of the room increases because the refrigerator is releasing heat to the room and Delta E. It's going to be negative the contents inside the fridge to lose energy so that their temperature decreases. So the sign is going to be negative. Thanks for watching my video and I hope it was helpful