SeniorPhysics Graded Assignment Help-Horizontal/Vertical Displacement

AI Thread Summary
The discussion revolves around a physics homework problem involving the horizontal and vertical displacement of a baseball rolled off a 20-foot tall roof. The student is uncertain about which equations to use for calculating the time the ball is in the air and the distance to the pool. Key equations mentioned include horizontal displacement at constant velocity and vertical displacement due to free fall. The problem intentionally mixes feet and meters to encourage conversion practice. Participants emphasize the importance of selecting the right equation based on known variables to solve the problem effectively.
Elle1121
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Homework Statement


A student is rolling a baseball off the roof of their house into their backyard pool.The house is 20 feet tall, and they roll the baseball off the flat roof at speed of 3 m/s towards the pool. How long is the ball in the air and how far away is the distance the pool must be from the house so that the ball hits the water?

I'm just not sure which of the three equations below to use!

Homework Equations


Horizontal displacement at a constant velocity: Change in X=v(t)
Vertical displacement due to free fall: 1/2g(t^2)
Vertical velocity due to free fall: V=gt

The Attempt at a Solution


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I took a stab at it, and I got two seconds for the time and 20 feet for the distance. I'm pretty sure they're both wrong though. Thanks for the help!
 
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Can you show your working? For example how did you get 2s for the time to fall 12ft (6m) ?
 
Hi Elle1121. http://img96.imageshack.us/img96/5725/red5e5etimes5e5e45e5e25.gif

Elle1121 said:
I'm just not sure which of the three equations below to use! [...]

Vertical displacement due to free fall: 1/2g(t^2)
The best advice is that you use the equation which is going to help you get the answer! Consider the equation

x = ½gt²

This has two variables, and if either is known you can use the equation to calculate the other variable. Is that going to help you here?

It seems that this problem statement mixes feet and meters, or is this your typing mistake?
 
Last edited by a moderator:
NascentOxygen said:
Hi Elle1121. http://img96.imageshack.us/img96/5725/red5e5etimes5e5e45e5e25.gif The best advice is that you use the equation which is going to help you get the answer! Consider the equation

x = ½gt²

This has two variables, and if either is known you can use the equation to calculate the other variable. Is that going to help you here?

It seems that this problem statement mixes feet and meters, or is this your typing mistake?
The problem mixes feet and meters on purpose; my teacher wants us to get used to converting them. Also, thank you so much for your help!
 
Last edited by a moderator:

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