• Support PF! Buy your school textbooks, materials and every day products Here!

Help w/ projecetile motion w/ angled launch problem

  • #1

Homework Statement


A bowling ball rolls off an angled roof. The roof is sloped downward at 18.4 degrees and it is 12m above the ground. The question is how long does it take the ball to hit the ground?


Homework Equations


Δx=viΔt+1/2a(Δt)^2
I know this is the equation I have to use but I'm having trouble isolating t.

The Attempt at a Solution


I used quad formula and ended up getting Δt=1.56s but I don't think that's right. The working equation I got was Δt=(-2ghi)^(1/2)/g .I assumed Vi was 0. I don't know how to do this, help please!
 
Last edited:

Answers and Replies

  • #2
PeterO
Homework Helper
2,425
46

Homework Statement


A bowling ball rolls off an angled roof. The roof is sloped downward at 18.4 degrees and it is 12m above the ground. The question is how long does it take the ball to hit the ground?


Homework Equations


Δx=viΔt+1/2a(Δt)^2
I know this is the equation I have to use but I'm having trouble isolating t.

The Attempt at a Solution


I used quad formula and ended up getting Δt=1.56s but I don't think that's right. The working equation I got was Δt=(-2ghi)^(1/2)/g .I assumed Vi was. I don't know how to do this, help please!
How far down the roof did the ball roll before launching of the edge? In other words; at what speed did the ball leave the roof?

EDIT: and is the time you are after, the time taken after it leaves the roof, or the time taken after it was released at the ridge of the roof and began rolling?
 
Last edited:
  • #3
57
1
I think it might be missing some information.

the angle is there for some reason.
 
  • #4
That's all the info to this problem and I would assume it's asking for how the ball takes to hit the ground after it's left the roof.
 
  • #5
PeterO
Homework Helper
2,425
46
That's all the info to this problem and I would assume it's asking for how the ball takes to hit the ground after it's left the roof.

If that is all the information that is provided then the answer is: "this problem is incalculable due to insufficient information"

Have you entered the question in the exact words in which the original question was stated?

It looks more like your interpretation of the question.
 
  • #6
Well, here's the exact question. A bowling ball rolls off an angled roof. The roof is sloped downward at 18.4°, and the eaves are 12.0 meters above the ground. a.)How long does it take the ball it hit the ground?
 
  • #7
PeterO
Homework Helper
2,425
46
Well, here's the exact question. A bowling ball rolls off an angled roof. The roof is sloped downward at 18.4°, and the eaves are 12.0 meters above the ground. a.)How long does it take the ball it hit the ground?
What is part b, c, etc
 

Related Threads on Help w/ projecetile motion w/ angled launch problem

Replies
4
Views
1K
  • Last Post
Replies
4
Views
2K
Replies
4
Views
1K
Replies
5
Views
13K
  • Last Post
Replies
2
Views
984
Replies
5
Views
19K
Replies
5
Views
573
Replies
4
Views
3K
Replies
3
Views
10K
Replies
3
Views
2K
Top