Please help. Lol it’s easy

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.

Suppose you have three polarizing filters, with the second at an angle of 42∘ to the first and the third at an angle of 90∘ to the first. by what perfect will the original intensity of unpolarized light be reduced to after passing through all three filters?

Hydrogen and helium are both members of?