What do i do on this rubixs cube

The car hoist allows the car to be driven onto the platform, after which the rear wheels are raised. if the loading from both rear wheels is 1380 lb, determine the force in the hydraulic cylinder ab. neglect the weight of the platform itself. member bcd is a right-angle bell crank pinned to the ramp at c. the force is positive if in tension, negative if in compression.

Explain why electric current cannot exist if a current doesn't have a voltage source.

Of is j/kg·k. if a 2.6 kg of isk to k,is ?