Calculating Normal Force Exerted by Floor on Feet/Hands

In summary, the problem involves calculating the normal force exerted by the floor on each hand and foot of a person whose weight is 587N. The person is doing push-ups with a length of 0.817m from their centre of gravity to their feet and 0.414m to their hands. The attempted solution involves using the equation for moments and solving for the end reactions in 2-dimensions before finding the forces on each limb.
  • #1
Hypnos_16
153
1

Homework Statement


A person whose weight is W = 587 N doing push-ups.
Assume L1 = 0.817 m (Centre of Gravity to Feet) and L2 = 0.414 m. (Centre of Gravity to Hands) Calculate the normal force exerted by the floor on each hand (enter first) and each foot, assuming that the person holds this position

Weight = 587N
Length to Feet = 0.817m
Length to Hands = 0.414m

Homework Equations



I think I'm over thinking this one, but I've tried solving it as if it were a bridge problem. But to no prevail.

The Attempt at a Solution



F x d
587 x 0.817 = 479.6
479.6 / 2 = 239.8 by his feet

F x d
587 x 0.414 = 243.0
243.0 / 2 = 121.5 by his hands
 
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  • #2
This sounds like a simple equilibrium problem - try using your equation for moments about either the hands or feet. Solve for the end reactions in 2-dimensions and then solve for each limb.
 

What is normal force?

Normal force is the force exerted by a surface on an object that is in contact with it. It is always perpendicular to the surface and acts as a support force to prevent the object from falling through the surface.

How do you calculate normal force?

To calculate normal force, you need to know the mass of the object, the gravitational acceleration, and the angle of the surface. The formula for normal force is FN = mgcosθ, where FN is the normal force, m is the mass, g is the gravitational acceleration, and θ is the angle of the surface.

Why is calculating normal force important?

Calculating normal force is important because it helps us understand the forces at work in a given situation. It is particularly useful in physics and engineering, where knowing the normal force can help determine the stability and safety of structures and objects.

What factors can affect the normal force?

The normal force can be affected by the mass of the object, the gravitational acceleration, the angle of the surface, and the coefficient of friction between the object and the surface. Changes in any of these factors can alter the amount of normal force exerted on an object.

Can the normal force be greater than the weight of the object?

Yes, the normal force can be greater than the weight of the object. This is because the normal force is determined by the angle of the surface and can vary depending on the situation. For example, if an object is on an inclined plane, the normal force will be greater than the weight of the object if the angle of the plane is steep enough.

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