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

Energy problem

  • Thread starter lzh
  • Start date
lzh
111
0
1. Homework Statement
Karen has a mass of 54 kg as she rides the
up escalator at Woodley Park Station of the
Washington D.C. Metro. Karen rode a dis-
tance of 59:5 m, the longest escalator in the
free world.
The acceleration of gravity is 9:8 m=s2 :
How much work did the escalator do on
Karen if it has an inclination of 29:4±? Answer
in units of J.


2. Homework Equations
W=F*x*cos(theta)
where F= force, x is displacement and theta is the angle between the 2


3. The Attempt at a Solution
I first drew a force diagram. And used it to figure out this:
mg=529.2N
F=529.2*cos60.6=259.786N <-force of escalator
Next i plugged it into the Work equation:
the angle between the displacement and force is 0, so cos(theta)=1:
W=259.786*59.5*1=15457.28285J

is this right? I just need a confirmation, because I can't afford to get this wrong. Ty in advance
 

Answers and Replies

225
0
looks good!
 
225
0
but using 60 instead of the exact value makes your answer inaccurate
 
lzh
111
0
60? for:
F=529.2*cos60.6=259.786N <-force of escalator
 
225
0
haha, sorry, I didn't see the .6
 

Related Threads for: Energy problem

  • Last Post
Replies
3
Views
987
  • Last Post
Replies
24
Views
965
  • Last Post
Replies
1
Views
774
  • Last Post
Replies
2
Views
2K
  • Last Post
Replies
4
Views
899
  • Last Post
Replies
1
Views
2K
  • Last Post
Replies
7
Views
1K
  • Last Post
2
Replies
33
Views
4K
Top