Topic: Basic Physics Problem question

[bryanrz]

A catapult is used to launch a ball at angle Theta=40 degrees. Determine the initial speed of the ball if range of the ball is 20 feet. initial position of the ball is x=0 and y=15 inches.

Anyone with some experience in physics?

I guess I just cant seem to figure out or find the correct equations I need.

Thanks for the help

[81 shortbed]

Basic physics? There's an oxymoron.


Sent from my iPhone using Tapatalk

[jrock]

It's been a while but I believe you break this into two parts. The deceleration and the re acceleration of the ball vertically, using the hight it went with the force of gravity on it to find how fast it would have to start to get that high. And how long it would be in the air. Then figure how fast the ball would have to be going to go 20 ft in that amount of time. Then based on the angles you could determine the initial speed.

This may be completely wrong. It's been a very long time since I've done this

[*FFC*]

Why does it not surprise me Jerome has some insight on this?

I used to be able to do this stuff, but that was..... a "few" years ago. Good luck!

[emsvitil]

What about air resistance ?

[Bam]

Figure out the time it takes for the ball to drop 15 inches in the y direction. Then figure out what velocity is needed to launch the ball 20ft in that amount of time.

[ryantowry_81]

You need to split the velocity into its horizontal and vertical components and remember gravity only acts on the vertical component and relate the two via trig relations and you should be able to solve for velocity given the angle and distance you want to travel. I can give you the formula but that would be to easy. Relate your distance in respect to time and it will fall out.

[dayodaman]