# General Physics Question -- Max height of a projectile

• Jerret Spenst
In summary: If an object is propelled straight up from ground level, and is unaffected by wind or other forces, and it takes say, 4.6 seconds for it land back down, can its max height be calculated? If so, what's the answer and math? Thanks!Yes, if the object is not subjected to air resistance. The max height can be calculated using the following formula:h = (G*ac)1/2Where h is the max height, G is the gravitational force, and ac is the acceleration of the object.
Jerret Spenst
When an object is thrown or propelled upwards and it meets the point at deceleration and drops; what is that point called, where the object is not moving in either direction?

Jerret Spenst said:
When an object is thrown or propelled upwards and it meets the point at deceleration and drops; what is that point called, where the object is not moving in either direction?
Welcome to the PF.

"Point of inflection?"

Thank you! Now in that state, could you propose that there would be a new force acting on the object or even the loss of one.

Jerret Spenst said:
Thank you! Now in that state, could you propose that there would be a new force acting on the object or even the loss of one.
Neglecting air resistance, there is only the force of gravity acting on the thrown object, and its acceleration (downwards) is constant.

True, but I'd like to discuss the possibility of theoretical forces not yet discovered or applied to general physics.

Jerret Spenst said:
True, but I'd like to discuss the possibility of theoretical forces not yet discovered or applied to general physics.
We don't allow speculation or theory development at the PF. We discuss mainstream science, as published in the peer-reviewed literature and mainstream textbooks.

Not a problem! Thank you for the previous answer!

berkeman
Jerret Spenst said:
True, but I'd like to discuss the possibility of theoretical forces not yet discovered or applied to general physics.
Why bother trying to introduce an extra force when the whole classical process can be calculated and predicted as accurately as you choose, using the existing classical forces - until you get to the scale of Relativity or QM.
PF protects itself (and you) from such whimsy.

berkeman
If an object is propelled straight up from ground level, and is unaffected by wind or other forces, and it takes say, 4.6 seconds for it land back down, can it's max height be calculated? If so, what's the answer and math? Thanks!

RTM said:
If an object is propelled straight up from ground level, and is unaffected by wind or other forces, and it takes say, 4.6 seconds for it land back down, can it's max height be calculated? If so, what's the answer and math? Thanks!
Are you familiar with the Kinematic Equations of Motion for Constant Acceleration (gravity)?

RTM
Yes, but long time. Will brush up on it, and figure it out! Will be a good exercise. Thanks!

The Hyperphysics website has a concise summary:

http://hyperphysics.phy-astr.gsu.edu/hbase/hframe.html

The Wikipedia page for Equations of Motion is good too, with lots more detail. I think the equations for motion given constant acceleration are about halfway down the long Wikipedia page...

RTM
Oops, that Hyperphysics link takes you to the top level. Click on Mechanics in the upper left, and then on Velocity and Acceleration...

RTM
thank you.

## 1. What is the formula for calculating the maximum height of a projectile?

The formula for calculating the maximum height of a projectile is h = (v^2 * sin^2(theta)) / (2 * g), where h is the maximum height, v is the initial velocity, theta is the angle of launch, and g is the acceleration due to gravity.

## 2. How does air resistance affect the maximum height of a projectile?

Air resistance can decrease the maximum height of a projectile by slowing it down and reducing its overall velocity. This results in a shorter flight time and a lower maximum height.

## 3. What role does gravity play in determining the maximum height of a projectile?

Gravity is the main factor that determines the maximum height of a projectile. As the projectile travels upwards, gravity slows it down until it eventually reaches its maximum height and begins to fall back to the ground.

## 4. Can the maximum height of a projectile be greater than the initial height?

Yes, the maximum height of a projectile can be greater than the initial height as long as the angle of launch is not 90 degrees and there is no air resistance present.

## 5. How does changing the angle of launch affect the maximum height of a projectile?

Changing the angle of launch can significantly affect the maximum height of a projectile. A launch angle of 45 degrees will result in the maximum height, while any angle greater or less than 45 degrees will result in a shorter maximum height.

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