# What is the normal force when a 40 kg person jumps and is accelerating at 3 m/s2 upward while in contact with the ground?

## F is up, +

F - m g = m a

F = m(g+a) = 40 (9.81+3)

## Well, let me tell you, when someone jumps, the ground gets really excited and applies a force to support them. This force is called the normal force. In this case, the person is accelerating upward, which means the normal force needs to be greater than their weight to lift them. So, the normal force would be equal to the weight of the person plus the additional force required for the upward acceleration. But don't worry, I won't leave you hanging. If we use the formula F = m * a, where F is the force, m is the mass, and a is the acceleration, we can calculate the force. The person's mass is 40 kg and the acceleration is 3 m/s^2. So, the force would be 40 kg * 3 m/s^2 = 120 N. Therefore, the normal force would be 120 N. That's a pretty uplifting force, if you ask me!

## To find the normal force acting on a person while jumping, we need to consider the forces acting on the person in equilibrium.

The normal force is the force exerted by a surface to prevent an object from falling through it.

In this case, the normal force would be equal in magnitude and opposite in direction to the gravitational force acting on the person.

The gravitational force acting on a person can be calculated using the formula:

Weight = mass × acceleration due to gravity

Weight = 40 kg × 9.8 m/s²

Weight = 392 N

Since the person is accelerating at 3 m/s² upward, the net force acting on the person can be calculated using Newton's second law:

Net force = mass × acceleration

Net force = 40 kg × 3 m/s²

Net force = 120 N

In equilibrium, the net force is equal to zero. Therefore, the normal force would be:

Normal force = Weight - Net force

Normal force = 392 N - 120 N

Normal force = 272 N

Therefore, the normal force acting on the person is 272 N.

## To calculate the normal force acting on the person while in contact with the ground, we need to consider Newton's second law of motion, which states that the net force acting on an object is equal to its mass multiplied by its acceleration.

Here's how you can find the normal force:

1. Identify the known values:

- Mass of the person, m = 40 kg

- Acceleration, a = 3 m/s² (upward)

2. Determine the net force acting on the person:

- Net force (F_net) = mass (m) × acceleration (a)

- F_net = 40 kg × 3 m/s² = 120 N (upward)

3. Evaluate the normal force:

- The normal force (F_normal) is equal in magnitude but opposite in direction to the net force acting on the person.

- Therefore, the normal force is 120 N but directed downward.

So, the normal force acting on the person when they jump and accelerate at 3 m/s² upward is 120 N, directed downward.