Robert uses a force of 22 newtons to move a 100 lb box a distance of 4 meters. How much work has he done? 50 newton-meters
88 newton-meters
400 newton-meters
2,200 newton-meters

Acatapult is tested by roman legionnaires. they tabulate the results in a papyrus and 2000 years later the archaeological team reads (distances translated into modern units): range = 0.4 km; angle of launch = π/5 rad; landing height = launch height. what is the initial velocity of launch of the boulders if air resistance is negligible?

Aresistor with an unknown resistance is connected in parallel to a 9 ω resistor. when both resistors are connected in parallel to an emf source of 21 v, the current through the unknown resistor is measured with an ammeter to be 4 a. what is the resistance of the unknown resistor? answer in units of ω.

Which component of the earth’s atmosphere is decreased due to photosynthesis?