A ball with a mass of 1 kilogram is at the top of a frictionless ramp 10 meters above the ground. The ball rolls down the incline and launches from a height of 2 meters and an angle of 30 degrees above the ground. (This picture was created in Creo.) Create a function that calculates the horizontal distance as a function of initial height, launch height, and launch angle. Calculate the horizontal distance the ball will land from the end of the ramp. Solve for the angle that will optimize the horizontal distance. How will the horizontal distance change if this were performed on the Moon instead of on the Earth’s surface? Assume the acceleration due to gravity on the Moon’s surface is 1/6 that of Earth. Use the Chart Component to depict how the horizontal landing distance changes as a function of angle. Use a 3D Plot to show how the horizontal landing distance changes as a function of ramp height and launch angle. Assume the ball starts at a height of 10 meters. The worksheet should contain sufficient documentation to stand on its own; someone unfamiliar with the initial problem should be able to understand what is being calculated. Find the Mathcad Community Challenge Guidelines here!

16-Pearl

Question

Mathcad Community Challenge May 2023 - Optimize Trajectory for Maximum Horizontal Distance

Forum|Forum|2 years ago
May 1, 2023
15 replies
23571 views

A ball with a mass of 1 kilogram is at the top of a frictionless ramp 10 meters above the ground. The ball rolls down the incline and launches from a height of 2 meters and an angle of 30 degrees above the ground.

(This picture was created in Creo.)

Create a function that calculates the horizontal distance as a function of initial height, launch height, and launch angle.
Calculate the horizontal distance the ball will land from the end of the ramp.
Solve for the angle that will optimize the horizontal distance.
How will the horizontal distance change if this were performed on the Moon instead of on the Earth’s surface? Assume the acceleration due to gravity on the Moon’s surface is 1/6 that of Earth.
Use the Chart Component to depict how the horizontal landing distance changes as a function of angle.
Use a 3D Plot to show how the horizontal landing distance changes as a function of ramp height and launch angle. Assume the ball starts at a height of 10 meters.

The worksheet should contain sufficient documentation to stand on its own; someone unfamiliar with the initial problem should be able to understand what is being calculated.

Find the Mathcad Community Challenge Guidelines here!

F

Fred_Kohlhepp

23-Emerald I

Can we assume that the ramp angle (from 10 meters) is also 30 degrees? (Otherwise the horizontal velocity requested in #1 is not fixed. Or do you want that discussed too?

D

DaveMartin

Author

16-Pearl

The function should calculate horizontal distance, not velocity.

W

Werner_E

25-Diamond I

@DaveMartin wrote:

The function should calculate horizontal distance, not velocity.

Yes, that is clear, but the distance will probably depend on the speed reached.
And this still does not answer the question whether the two legs of the ramp actually enclose a right angle, as one could assume on the basis of the drawing.

So is the angle of the longer ramp 60 degree to the horizontal plane or should it be considered variable?

P

ppal_255687

18-Opal

So i get

for the first iteration . Used Moment of inertia of hollow sphere .

Anyone can confirm or dissent before I go further?

W

Werner_E

25-Diamond I

I have not spent much time on it so I may had made mistakes, but I ended up at approx, 17 meters

The desired function would be

or

P

ppal_255687

18-Opal

Comments on my approach - Prime 9 attached

3_May-PTC-Challenge.zip

W

Werner_E

25-Diamond I

Since the size of the sphere is not specified, I assume that it is simplified to be a point mass and things like rotational energy should not matter. @DaveMartin could go into more detail about this.

EDIT: Ahh, I just noticed that he already wrote that the diameter of the ball should be ignored as well. So I guess that we should also assume that all kinetic energy is in translation and none in rotation. The ball is sliding down and up the ramp and not rolling, hmm...

D

DaveMartin

Author

16-Pearl

Yes, please consider this a point mass. This problem was inspired by a high school physics problem cited by NASA in the 1960s. My intent was for people to consider the potential energy for the object at the top of the ramp and convert that into the kinetic energy as it comes off the ramp. That will give you the velocity of the object, and then you can plug that into trajectory equations like:

https://www.physicsgoeasy.com/maximum-range-of-projectile-formula/?utm_content=expand_article

For optimizing the distance in step 3, people should have an intuitive sense that the angle would be 45 degrees. I wanted to see how people would calculate that in Mathcad.

The main point was to get to charts and 3D plots in steps 5 and 6.

I should have probably used the word "slides" instead of "rolls" in the explanation of the problem. I will see if I can edit that. You can ignore friction, air resistance, rotational inertia, heat dissipation, or any other effects. I wasn't looking for anything beyond potential energy going into kinetic energy.

W

Werner_E

25-Diamond I

So anyway here is my entry - out of competition as it was created in Mathcad 15. But this version allows a much quicker and faster workflow and is significantly more convenient to use. Quite apart from the fact that it is also more powerful in terms of functionality.

I briefly tried converting the file to Prime 9, but despite the fact that it would have required a lot of reformatting to make it look anything like the same, I also had to refuseto put up with the many shortcomings of Prime and the converter to bang around. The well known auto-label bug has struck again - h has become a constant, g an undefined variable without a way to change it. And Prime's inability to deal with incomplete functions would have required a workaround in calculating the optimal angle. I didn't even get as far as the plots then. I quickly gave up trying to create a Prime Worksheet, very disgusted, and instead attached a PDF Print in addition to the Mathcad file.

Have fun!

Here the pics of the two pages

1_WE_20230504_May-Challenge.zip

2_WE_20230504_May-Challenge.pdf

D

DaveMartin

Author

16-Pearl

Looks like you got the trick answer to #4. The acceleration due to gravity falls out of the equation. So it doesn't matter if you're doing it on the Earth, the Moon, or Pluto.

F

Fred_Kohlhepp

23-Emerald I

Solution attached, Prime 4.0 Express

1_challenge-5_23-chgedA.zip

J

JeffH1

16-Pearl

My submission in Prime 9.0 format.

1_Challenge-May-2023---JPH.zip

ttokoro

21-Topaz I

Ignore rotational kinetic energy. Prime 9. No Chart Component but x-y plot. Without units to solve.

t.t.

1_May2023-PTC-Challenge.zip

A

AlanStevens

19-Tanzanite

Here's my limited attempt with Prime 8 Express:

1_MayChallenge.zip

J

JE_9022802

3-Newcomer

If it's a ball, why does the incline need to be frictionless? The intent of a ball is to have it rotate. For that to occur, you need nominal friction.

D

DaveMartin

Author

16-Pearl

If you want the incline to have friction, add friction. If you want to incorporate that and rotational inertia, have at it.

I will repeat my original intent. I modified an old high school problem, where the intent was for people to use the potential energy to find the initial velocity to calculate a trajectory. Anything else you want to add to the problem is up to you.

As with the previous Mathcad Challenges, the point isn't the answer you get, but how you choose to approach the problem with the tools in Mathcad.