Art a assume that the cart is free to roll without friction and that the coefficient of static friction between the block and the cart is μs. derive an expression for the minimum horizontal force that must be applied to the block in order to keep it from falling to the ground. express your answer in terms of m, m, μs, and g.

An insulated 40 ft^3 rigid tank contains air at 50 psia and 120°f. a valve connected to the tank is now opened, and air is allowed to escape until the pressure inside drops to 25 psia. the air temperature during this process is kept constant by an electric resistance heater placed in the tank. determine the electrical work done during this process.

Lightning is an example of what phenomenon? a release of a large amount of energy an absorption of a large amount of energy a natural electric circuit a natural electric current

Which of the choices are parts of an atom? select all that apply. a.) compound b.) electron c.) neutron d.) molecule e.) photon f.) proton g.) element