Normal Force Problem: Calculating Magnitudes

[johnson.3131]

Homework Statement

A 41 kg crate rests on a horizontal floor, and a 53 kg person is standing on the crate.

(a) Determine the magnitude of the normal force that the floor exerts on the crate.


(b) Determine the magnitude of the normal force that the crate exerts on the person.

Homework Equations

The Attempt at a Solution

Normal force is usally the opposite of weight so i converted the kg to Newtons and thought maybe that was the answer?

 

[LowlyPion]

Homework Statement

A 41 kg crate rests on a horizontal floor, and a 53 kg person is standing on the crate.

(a) Determine the magnitude of the normal force that the floor exerts on the crate.

(b) Determine the magnitude of the normal force that the crate exerts on the person.

Homework Equations

The Attempt at a Solution

Normal force is usally the opposite of weight so i converted the kg to Newtons and thought maybe that was the answer?

Welcome to PF.

Yes force is in Newtons. And Normal force is what the stuff on top of it weighs right?

So How much do the crate/guy weigh on te floor and how much does the guy weigh on the crate?

 

[baba89]

The normal force is the force exerted by a surface on an object that is in contact with it. In this problem, the floor exerts a normal force on the crate, and the crate exerts a normal force on the person standing on it. The magnitude of the normal force can be calculated using the formula F = mg, where m is the mass of the object and g is the acceleration due to gravity (9.8 m/s^2).

(a) To determine the magnitude of the normal force that the floor exerts on the crate, we can use the formula F = mg, where m is the mass of the crate (41 kg) and g is the acceleration due to gravity (9.8 m/s^2). This gives us a normal force of 401.8 N.

(b) To determine the magnitude of the normal force that the crate exerts on the person, we can use the same formula, but with the mass of the person (53 kg). This gives us a normal force of 519.4 N.

It is important to note that the normal force is not always equal to the weight of an object. In this case, the normal force exerted by the crate on the person is greater than the weight of the person, because the person is standing on the crate and the crate is also supporting its own weight.

 

[thomate1]

Your attempt at a solution is partially correct. The normal force is indeed the opposite of weight, but it is not the same as weight. The normal force is the force that a surface exerts on an object in contact with it, perpendicular to the surface. In this case, the floor is exerting a normal force on the crate and the crate is exerting a normal force on the person.

To calculate the magnitude of the normal force in each case, you can use the equation F = ma, where F is the force, m is the mass, and a is the acceleration. In this case, the acceleration is 0, since both the crate and the person are at rest.

(a) To find the normal force exerted by the floor on the crate, you can use the equation F = ma, where F is the normal force, m is the mass of the crate (41 kg), and a is the acceleration (0). This gives you F = (41 kg)(0) = 0 N. This means that the normal force exerted by the floor on the crate is 0 N.

(b) To find the normal force exerted by the crate on the person, you can use the same equation, but with the mass of the person (53 kg). This gives you F = (53 kg)(0) = 0 N. This means that the normal force exerted by the crate on the person is also 0 N.

In this scenario, both the crate and the person are at rest, so the normal forces are equal and opposite, and cancel each other out. However, if either the crate or the person were to move, the normal forces would change accordingly. It's important to note that the normal force is not always equal to the weight of an object, as it depends on the other forces acting on the object.