You wish to lift a 400 lb car engine a vertical distance of 3 ft using a strong rope. Unfortunately, your hand crank winch can only generate 100 lb of tension in your rope. In order to overcome this obstacle, you use a multiple pulley system (block and tackle) to lift the engine.

What is the mechanical advantage of this system?

An astronaut in space cannot use a scale or balance to weigh objects because there is no gravity. but she does have devices to measure distance and time accurately. she knows her own mass is 77.4 kg , but she is unsure of the mass of a large gas canister in the airless rocket. when this canister is approaching her at 3.50 m/s , she pushes against it, which slows it down to 1.30 m/s (but does not reverse it) and gives her a speed of 2.60 m/s . what is the mass of the canister?