HELP ME PLEASE basic physics!

  • Thread starter AfroQueen
  • Start date
  • #1
7
0

Homework Statement


in the design of a spermarket there are to be several ramps connecting different parts of the store. customers will have to push grocery cats up the ramps and it is obviously desirable that this is not be too difficult. The engineer has done a survey and found that almost no noe complains if the force directed up the ramp is no more than 20N. Ignoring friction at what maximum angle (theta) should the ramps be built assuming a full 30kg grocery cart.


Homework Equations


F=mg
mg sin(theta)= Fapp
Fapp= force applied=20N

The Attempt at a Solution


ok i understand this question or so i thought but every time i try to work it out i dont get the answer which is supposed to be 5.9 degrees... Here's my work
F=mg
F=30*9.8
F=294N

mg *sin(theta)=20N
294*sin(theta)=20N
sin(theta)=.068027
theta=3.9 ????
 

Answers and Replies

  • #2
How did you create your second equation?
 
  • #3
The answer must be a mistake..
You're work appears fine to me.
 
  • #4
7
0
How did you create your second equation?

the secondd equation comes because friction is ignored in this problem so in the equation mg*sin(theta)-(static kinetic energy)*cos(theta) the static kinetic energy doesn't apply so you can think of it as 0... so you're left with mg*sin(theta) and since you need to make sure that the customers dont exceed a certain force (because they will complain) i set that equation equal to that certain force and that would give you the maximum angle...
 
  • #5
7
0
The answer must be a mistake..
You're work appears fine to me.

thats what i keep saying to myself but my friend said she was able to get the same answer as the one provided in the book...
 
  • #6
55
0
is your calculator in the correct mode?
 
  • #7
7
0
is your calculator in the correct mode?

yeahi tried it in degree mode and i tried just putting it into radian mode and then just converting but i still get the same wrong answer...
 
  • #8
7
0
is your calculator in the correct mode?

also do you think its has anything to do with my work?
or equations?
 

Related Threads on HELP ME PLEASE basic physics!

  • Last Post
Replies
1
Views
5K
  • Last Post
Replies
1
Views
3K
  • Last Post
Replies
3
Views
1K
  • Last Post
2
Replies
39
Views
9K
  • Last Post
Replies
16
Views
1K
  • Last Post
Replies
1
Views
2K
  • Last Post
Replies
7
Views
1K
Replies
2
Views
2K
Replies
4
Views
2K
  • Last Post
Replies
14
Views
10K
Top