A cheerleader lifts his 39.1 kg partner straight up off the ground a distance of 0.378 m before releasing her. Assume the partner’s velocity is zero at the beginning and the end of the lift. The acceleration of gravity is 9.8 m/s 2 . If he does this 18 times, how much work has he done? Answer in units of J.

Why are biogeochemical cycles important? earth is a closed system. that means the amount of rocks, metals, carbon, nitrogen, oxygen, and water on so, it is essential that biogeochemical these materials as they move through earth's subsystems.

Which of these statements is true? a. quarks pair with leptons to form protons and neutrons. b. quarks pair with bosons to form photons. c. quarks pair with photons to form protons and neutrons. d. quarks pair with other quarks to form protons and neutrons. e. quarks pair with electrons to form protons.

Calculate the first and second velocities of the car with four washers attached to the pulley, using the formulas v1 = 0.25 m / t1 , and v2 = 0.25 m / (t2 – t1) where t1 and t2 are the average times the car took to reach the 0.25 and the 0.50 meter marks. record these velocities, to two decimal places, in table e.