# Acceleration Due to Gravity Question

• Cursed
In summary, the conversation discusses the acceleration of an object in free fall and whether it is affected by initial velocity. It is concluded that in ideal physics, the acceleration due to gravity should be 9.8m/s and that thrust is simply a force that acts against the mass, not taking into account the speed at which it is applied.

#### Cursed

Quick question...

If you were to throw an object (such as a baseball) straight downward, would the acceleration of the object still be -9.8m/s/s?

Ignoring aerodynamic drag, and assuming that the distance from Earth isn't signicantly large, then velcocity doesn't affect the gravitational acceleration.

For a similar example, imagine a rocket in space. It's acceleration is a function of thrust versus mass of the rocket and is also independent of the rockets velocity.

Jeff is right, from what I can tell. The initial velocity plays no part in the acceleration of an object in free fall.

Quick question there, Jeff. When you say thrust, are you basically counting it as a 'force' that acts against the mass? I'm relatively new to physics so I'm just trying to understand what I can.

Before the object leaves your hand, its acceleration may be higher than gravitational acceleration. But after it comes off your hand, the acceleration is exactly g (not taken air drag into account) because gravity is only force that exerts on.

think about it if you throw it straight down its has an initial velocity only. In ideal physics your acceleration due to gravity should be only 9.8m/s on free falling objects.

MurdocJensen said:
When you say thrust, are you basically counting it as a 'force' that acts against the mass?
Yes, thrust is simply a force, and doesn't take into account the speed at which the force is applied. Force times speed equals power, for example, force in lbs, times speed in mph, divided by 375 (conversion factor) calculates horsepower.

## What is acceleration due to gravity?

Acceleration due to gravity, also known as gravitational acceleration, is the rate at which an object falls towards the Earth due to the force of gravity. It is denoted by the symbol "g" and has a value of 9.8 meters per second squared on Earth.

## Why does acceleration due to gravity vary on different planets?

The acceleration due to gravity varies on different planets because it depends on the mass and radius of the planet. The larger the mass and radius of a planet, the stronger its gravitational pull, resulting in a higher acceleration due to gravity. For example, the acceleration due to gravity on Jupiter is 24.8 meters per second squared, while on Mars it is 3.7 meters per second squared.

## What factors affect the acceleration due to gravity?

The acceleration due to gravity is affected by the mass and distance between two objects. The greater the mass of an object, the stronger its gravitational pull will be. Similarly, the closer two objects are to each other, the stronger their gravitational pull will be, resulting in a higher acceleration due to gravity.

## How is acceleration due to gravity measured?

The acceleration due to gravity can be measured using a simple pendulum or by dropping objects from a height and measuring the time it takes for them to fall. It can also be calculated using the equation g = (GM)/r^2, where G is the gravitational constant, M is the mass of the larger object, and r is the distance between the two objects.

## Does acceleration due to gravity change with altitude?

Yes, acceleration due to gravity decreases with altitude. This is because as you move further away from the Earth's surface, the distance between you and the center of the Earth increases, resulting in a weaker gravitational pull. However, this change is minimal and can only be observed at very high altitudes.

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