FREE POINTS FOR EASY QUESTION An experimenter completes an experiment on which is the best light bulbs to use in a certain type of lamp. He tries 4 different light bulbs in the same lamp. He turns the lamp on with each type of light bulb for the same amount of time.

What is the manipulated variable in this experiment?

the amount of time the lamp is on

the lamp

the light bulbs

the amount of energy used

Aleaky 10-kg bucket is lifted from the ground to a height of 15 m at a constant speed with a rope that weighs 0.7 kg/m. initially the bucket contains 45 kg of water, but the water leaks at a constant rate and finishes draining just as the bucket reaches the 15-m level. find the work done. (use 9.8 m/s2 for g.) show how to approximate the required work by a riemann sum. (let x be the height in meters above the ground. enter xi* as xi.) lim n → ∞ n (9.8)(45−3 xi) i = 1 δx express the work as an integral. 0 dx evaluate the integral. (round your answer to the nearest integer.) j