Which of the following scenarios depicts work being done? (mark all correct answers) Group of answer choices

A person applies force to a couch, which stays in the same spot, until they are exhausted

Friction slows down a moving skateboard

A person applies force to a couch, moving it across the room

An air-standard stirling cycle operates with a maximum pressure of 600 psia and a minimum pressure of 10 psia. the maximum volume of the air is 10 times the minimum volume. the temperature during the heat rejection process is 100°f. calculate the specific heat added to and rejected by this cycle, as well as the net specific work produced by the cycle. use constant specific heats at room temperature. the properties of air at room temperature are r

Mechanical energy is when the amount of kinetic and potential energies added together remains the same. conserved created lost

The drag force, fd, imposed by the surrounding air on a vehicle moving with velocity v is given by fd = cdaρv 2/2 where cd is a constant called the drag coefficient, a is the projected frontal area of the vehicle, and ρ is the air density. an automobile is moving at v = 80 kilometers per hour with cd = 0.28, a = 2.3 m2, and ρ = 1.2 kg/m3.