You've got a flat tire. To lift your car, you make a homemade lever (see the figure (Figure 1)). A very light 1.6-m-long handle part is pushed down on the right side of the fulcrum and a 0.050-m-long part on the left side supports the back of the car. How hard must you push down on the handle so that the lever exerts an 6900- N force to lift the back of the car?

How hard you must push down on the handle is by applying a force of 215.63 N

The moment of a force about a point is the turning effect of the force about that point.

The moment of a force M = Fd where

Now, for you to lift up the car, the moment due to your force about the fulcrum, M equals the moment due to the force on back of car. M'

M = M'

FD = F'd where

Making F subject of the formula,we have

F = F'd/D

Substituting the values of the variables into the equation,we have

F = F'd/D

F = 6900 N × 0.050 m/1.6 m

F = 345 Nm/1.6 m

F = 215.625 N

F ≅ 215.63 N

So, how hard you must push down on the handle is by applying a force of 215.63 N

Learn more about moment of a force here:

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