8. For each statement, write true or false.(adsbygoogle = window.adsbygoogle || []).push({});

A)only the net force acting on an object can do work.

i think its TRUE.

B)no work is done on a particle that remains at rest.

i think its TRUE.

C)a force that is always perpendicular to the velocity of a particle never does work on the particle.

i think its TRUE.

^ please correct me if im wrong.. ^ thx.

6. A particle of mass m moves along the x axis. Its position varies with time according to x=2t^3 + 4t^2 where x is in meters and t is in seconds.

B)find the power delivered to the particle at any time t.

????

C)the work done by the force from t=0 to t=11

im guessing i have to integrate the equation 2t^3 + 4t^2 with 11 on top right of the integration sign and 0 on the bottom of the integration sign.

any comment will be hhelpful. thx in advance!

10. If a ski lift raises 100 passengers averaging 660N in weight to a height of 150m in 60s, at constant speed, what average power is required of the force making the lift?

I got P = W/t = mgh/t = 660N*150m/60s = 1650W = 1.6kW

did i do this right?

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# Homework Help: PHYSICS work/power/energy question

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