Frictional Force: Calculate on 43 kg Mass Inclined at 19 Degrees

[grouchy]

Homework Statement

a block is at rest on the incline shown in the figure. the coefficients of static and kinetic friction are s = 0.42 and k = 0.36 respectively. The acceleration of gravity is 9.8 m/s^2. the angle is 19 degrees.

what is the frictional force acting on the 43 kg mass? answer in units of N.

The Attempt at a Solution

I tried brake it up into components and still got it wrong, really have no idea how to do this problem.

 

[Bill Foster]

The friction coefficient is denoted by: μ
The Normal force is: N=mgcos(θ)
The frictional force is: μN=μmgcos(θ)

 

[grouchy]

yea, I get 167.3454417 as my answer (dont have to put it into significant figures for the homework) and its wrong...

 

[grouchy]

the angle of inclination is on the left, the object would slide to the left if it wasnt for the friction...if it makes a difference but I also tried to submit my answer as -167.3454417 and that was wrong too...

 

[Bill Foster]

What is the correct answer?

 

[grouchy]

I don't know the correct answer because I need to submit the homework online and it gives u like 7 chances, it only says if ur right or wrong

 

[Bill Foster]

Well, if it's looking for an answer in terms of N, and the frictional force is μN, and if μ=0.42, then in terms of N, the answer is 0.42N.

 

[eyehategod]

its been a long time since i did these types of problems but i think at rest the frictional force would be F=(mew*mg)-mgsin(theta)

 

[PhanthomJay]

Homework Statement

a block is at rest on the incline shown in the figure. the coefficients of static and kinetic friction are s = 0.42 and k = 0.36 respectively. The acceleration of gravity is 9.8 m/s^2. the angle is 19 degrees.

what is the frictional force acting on the 43 kg mass? answer in units of N.

The Attempt at a Solution

I tried brake it up into components and still got it wrong, really have no idea how to do this problem.

This is a duplicate post. I suggest calculating the value of the component of the gravity force acting down the plane. Then apply Newton 1 for bodies at rest to calculate the friction force. HINT: You won't need to know mu.

 

[xkaibob]

so is this problem equilibrium or not?

 

[PhanthomJay]

so is this problem equilibrium or not?

It is given that the block is at rest; hence, yes, it is in equilibrium.