A force of 5N acts on a 2 kg object that starts from rest. When the force has been acting for 2 s, the rate at which it is doing work is:(adsbygoogle = window.adsbygoogle || []).push({});

Here's how I tried to solve it.

Solve for acceleration, which I assumed was constant.

Code (Text):

a = F/m = 5N / 2kg = 2.5 m/s/s

Then use the displacement equation to find the distance traveled.

However, the only possible answer choices are:Code (Text):

x = xo + (vo)(t) + (1/2)(a)(t^2)

x = 0 + 0 + (1/2)(2.5 m/s/s)(2s)^2

x = 5m

Work = F * x = 5N * 5m = 25 J

Power = Work / t = 25J / 2s = 12.5 W

a) 5W b) 10W c) 25W d) 50W e) 75W

Where am I screwing up?

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# Homework Help: Simple work-energy problem

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