Question

You can keep a 1kg apple from falling to the ground by placing it on a table. What reaction force is resisting the force of the apple on the table?
1. Air resistance
2. Friction
3. Normal force
4. Tension
5. Gravity

Answer 1

The equilibrium condition allows finding the correct answer for the force that is resisting the weight of the apple is:

        3. Normal force

Newton's second law gives the relationship between force, mass and acceleration of bodies, in the special case that the acceleration is is called the equilibrium condition.

            ∑ F = 0

Where F is the external force.

The free body diagram is a diagram of the forces on bodies without the details of the shape of the body, in the attached we can see a scheme of the forces.

Let's write the equilibrium condition for the apple

          N - W = 0

          N = W

.

We can see that the only forces acting on the apple are its weights and reaction from the table called Normal.

Let's analyze the different answers:

1. False. The apple is not moving therefore the resistance is zero

2. False. The apple is not moving  so friction it with the table is  

3. True. The free-body diagram shows that the normal and the weight are equal

4. False. There is nothing to pull the apple so there is no tension

5. False. Gravity is the weight of the apple that is applied to the table, not from the table to the apple.

In conclusion using the equilibrium condition we can find the correct result for the force that is resisting the weight of the apple is:

        3. Normal force

Learn more here: brainly.com/question/2872207