When the truck is at rest, will the crate also be at rest?

  • Thread starter Thread starter javii
  • Start date Start date
  • Tags Tags
    Rest Truck
Join the discussion
Ask a follow-up here, or get your own question answered by working scientists, mathematicians and engineers — people, not an autocomplete.
Real named experts · corrections over time · the nuance an AI answer skips
4 replies · 2K views
javii
Messages
23
Reaction score
0

Homework Statement


I have attached the known information.
problem-2-png.113891.png

When the truck is at rest, will the crate also be at rest or will it slide
downwards?

Homework Equations


Sum F_y =0
G_max = (my_s)*N
G_min = (my_k) * N

The Attempt at a Solution


I did a Free body diagram on the crate (see the attached file)

The first step is finding the normal force.
Sum F_y =m*a_y =0
N-mg*cos(10)=1932.19 N

now i find the friction forces
G_ max=(my_s)*N= 0.70*1932.19=1352.53 N
G_min=(my_k)*N=0.50*1932.19=966.10 N

Now i will find F_II
F_II = m*g*sin(10) = 340.70 N

since G_max > F_II there is no motion downwards i,e a_x = 0

I am not sure if I have done it correct.
Thank you for your help.
 

Attachments

  • problem 2.PNG
    problem 2.PNG
    21.3 KB · Views: 878
on Phys.org
javii said:
N-mg*cos(10)=1932.19 N
I assume you mean N=mg*cos(10)=1932.19 N
javii said:
G_min = (my_k) * N
Only if it is moving. And it is mu, not my.
You can get the actual Greek character and subscript using the buttons just above the text area, Σ, X2, X2
javii said:
since G_max > F_II there is no motion downwards
Yes.
 
  • Like
Likes   Reactions: javii
haruspex said:
I assume you mean N=mg*cos(10)=1932.19 N

Only if it is moving. And it is mu, not my.
You can get the actual Greek character and subscript using the buttons just above the text area, Σ, X2, X2

Yes.
Yes i ment N=mg*cos(10)=1932.19 N (isolating for N)

So I don't have to calculate for G_min? Meaning I can skip this part in the calculations?
 
javii said:
Yes i ment N=mg*cos(10)=1932.19 N (isolating for N)

So I don't have to calculate for G_min? Meaning I can skip this part in the calculations?
Yes. You can assume the crate was placed statically. Until static friction is overcome, it is going nowhere.
I would have guessed there are more parts to the problem.
 
  • Like
Likes   Reactions: javii
haruspex said:
Yes. You can assume the crate was placed statically. Until static friction is overcome, it is going nowhere.
I would have guessed there are more parts to the problem.
haruspex said:
Yes. You can assume the crate was placed statically. Until static friction is overcome, it is going nowhere.
I would have guessed there are more parts to the problem.
Okay. Thank you very much. And yes there are more parts to the problem, i am trying to solve them now.