Does the size of a paper airplane affect how far it flies

Around faucet handle is part of a(n) a. lever b. screw c. inclined plane d. wheel and axle

What are two different ways you could find the value of a? explain these methods.

Assume you measured the mass of the cart to be (500 ± 1) g and the mass of the additional mass you put on the cart to be (500 ± 1) g as well. since the scale you are using in the lab cannot measure objects heavier than 600g you will have to sum up individual pieces and propagate the error. so what would be the mass and the standard error of the cart and the mass