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Physics
Classical Physics
Mechanics
Help to understand the concept of Power
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[QUOTE="Drakkith, post: 5748019, member: 272035"] Yes, the force would affect the velocity of the object, but it doesn't matter. That fact is already "built-in" to work and power. For example, applying a net force of 10 Newtons for 10 seconds on a 1kg object: ##a = \frac{f}{m} = \frac{10}{1} = 10 m/{s^2}## ##v = v_0 + at = 0 + 10*10 = 100 m/s## The distance the object moves over this time period is given by: ##x = x_0 + v_0t + 1/2at^2 = 0 + 0 + 1/2*10*10^2 = 500 m## The work required to get the object up to 100 m/s is just the same as its kinetic energy. ##k_e = 1/2mv^2 = 1/2*1*100^2 = 5,000 J## We can also calculate the work done using the force and the distance: ##W = f*d = 10 * 500 = 5,000 J## Power: ##P = W/t = 5,000/10 = 500 W## You need to use the [I]net [/I]force on the object in your calculation. In equilibrium there is no net force and no work is performed on the object by any of the forces. Note that you will still expend energy and perform work[I] on yourself[/I] because your body is not a perfectly efficient machine. Your muscles fibers constantly contract and relax just to hold an object at rest, your bones and muscles stretch and bend, the chemical reactions powering your muscles release a lot of energy simply as heat, etc. [/QUOTE]
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Help to understand the concept of Power
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