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

Can you help me please?

  • Thread starter Blubla
  • Start date
5
0
Hello all,

I have a little problem solving these 2 problems, guess you all can help me cuz its piece

of cake for you all.

Ok here we go:

1. Old faithful geyser in yellowstone national park shoots water every hour to a height of

40.0m. With what velocity does the water leave the ground?

2. A pendulum with a mass of 1 kg is released from a height of 1.5cm above the height of

its restin position. How fast will the pendulum be moving when it passes thorugh the

lowest point of its swing?

Dunno why when I saw this kind of problem(like number 1) ,only giving 1 value, is kinda

to solve for me..

Note: Sorry about my bad english :cool:
 

Answers and Replies

Doc Al
Mentor
44,827
1,083
To get detailed help, please show your work and point out where you got stuck.

Hint: Both problems can be solved using conservation of energy.
 
5
0
Errn.. Well, I cannot post any link cuz I dont have 15 posts nor image cuz it exceeds the

required size.

I can tell the answers, 1. Vf= 28m/s

2. Vf=0.55m/s

Thats what I have at the moment, is it correct?
 
Doc Al
Mentor
44,827
1,083
Show how you got those answers. (We don't need to see a diagram.)
 
5
0
PE = KE

vf^2= 2mgh/m=2gh

Vf^2=2*40*9.81

Vf^2=784.8

Vf=28.0m/s

----------------

PE = KE

I changed 15cm into m so it will be = 0.15

PE=mgh

PE=1(9,81)(0.15)

PE=1.5

KE=1/2mgv^2

KE= 1/2(1)

KE= 0.5

KE/PE= Vf^2

0.5/1.5=Vf^2

0.3=Vf^2(Apply square root to both side)

0.55=Vf


I got it this way.. tell me if Iam wrong
 
Nabeshin
Science Advisor
2,204
16
In the future, try to use a little more descriptive title. Perhaps something that actually pertains to the content of your inquiry.
 
5
0
Ok I will
 
Doc Al
Mentor
44,827
1,083
Your solutions look good to me.
 

Related Threads for: Can you help me please?

  • Last Post
Replies
1
Views
1K
Replies
2
Views
2K
Replies
3
Views
1K
Replies
6
Views
2K
Replies
5
Views
3K
Replies
10
Views
1K
Top