# Hacktivateed

5

## What do you get when you subtract force of air resistance from the force of gravity?

What do you get when you subtract the force of air resistance from the force of gravity? Net force is equal to the force of air resistance subtracted by the force of gravity.

## Is gravity stronger than air resistance?

As learned above, the amount of air resistance depends upon the speed of the object. Thus, more massive objects fall faster than less massive objects because they are acted upon by a larger force of gravity; for this reason, they accelerate to higher speeds until the air resistance force equals the gravity force.

Why do we ignore air resistance?

Air resistance is insignificant for heavy objects precisely because it doesn’t depend on the mass. This is because a force is just an interaction that tries to change the momentum of an object, and the momentum depends on the mass; the larger the mass, the larger the momentum, and the more force you need to change it.

### Does air resistance affect acceleration due to gravity?

With air resistance, acceleration throughout a fall gets less than gravity (g) because air resistance affects the movement of the falling object by slowing it down. How much it slows the object down depends on the surface area of the object and its speed.

### What is the direction of the net force on a falling skydiver before she reaches terminal velocity?

The net force and the acceleration on the falling skydiver is upward. An upward net force on a downward falling object would cause that object to slow down. The skydiver thus slows down. As the speed decreases, the amount of air resistance also decreases until once more the skydiver reaches a terminal velocity.

Why is a heavier object harder to accelerate than a lighter one?

As acceleration is inversely proportional to mass, if mass increases, the acceleration will reduce ( keeping the force constant). We see that as the mass increases, acceleration reduces. So a heavier object is harder to accelerate than a lighter object.

## Do heavier objects fall faster?

Answer 1: Heavy objects fall at the same rate (or speed) as light ones. The acceleration due to gravity is about 10 m/s2 everywhere around earth, so all objects experience the same acceleration when they fall.

## Why do 2 objects fall at the same time?

Consequently, the acceleration is a=Fm=GMR2, which is independent of the mass of the object. Hence any two objects that are subject only to the force of gravity will fall with the same acceleration and hence they will hit the ground at the same time.

What happens when air resistance is ignored?

When an object is dropped from rest (and we ignore air resistance) the time it takes to reach the ground depends only on the initial height and the acceleration of the object. In general, this air resistance will mean that an object dropped from a certain height will take longer to reach the ground.

### What if there was no air resistance?

If there is no air resistance, after you let go of an object the only force on it is the gravitational force. The gravitational force is proportional to the mass of the object. The acceleration of an object is proportional to the net force on the object and inversely proportional to the mass of the object.

### How much does air resistance affect a projectile?

As a projectile moves through the air it is slowed down by air resistance. Air resistance will decrease the horizontal component of a projectile. The effect of air resistance is very small, but needs to be considered if you want to increase the horizontal component of a projectile.

Do heavier objects fall faster with air resistance?

Galileo discovered that objects that are more dense, or have more mass, fall at a faster rate than less dense objects, due to this air resistance. Air resistance causes the feather to fall more slowly.

## How do you calculate the force of gravity?

Multiply the mass of the object in kilograms by 9.8, which is the acceleration due to gravity. An object dropped near the surface of the earth will accelerate at a rate of 9.8 meters per second squared. This is the gravitational force between the Earth and the object in question. Both objects exert an equal force on each other.

## What happens to an object when the resultant force is zero?

This is a single force that has the same effect on the object as all the individual forces acting together. If the resultant force is zero, a moving object will stay at the same speed.

What causes an object to undergo a specific change?

A force causes an object to undergo a specific change. Unbalanced forces cause changes in speed, shape or direction. Gravitational forces act between masses. Friction opposes motion.

### How is the acceleration of an object measured?

Note that the object could also change direction, for example if the resultant force acts at an angle. acceleration is measured in metres per second squared, m/s2. The same force could accelerate a 1 kg mass by 50 m/s2 or a 100 kg mass by 0.5 m/s2. You should see that it takes more force to accelerate a larger mass.