A heat engine operates with 70.0 kcal of heat supplied and exhausts 30.0 kcal of heat. How much work did the engine do?

Truck traveling west on the highway experiences an acceleration to the east. what could be the cause of this acceleration

Charge is distributed along the entire x-axis with uniform density λ. how much work does the electric field of this charge distribution do on an electron that moves along the y-axis from y = a to y = b? (use the following as necessary: a, b, ε0, λ, and q for the charge on an electron.)

Photons with the highest energy have the longest period