A Guide to Stress-Free College Life

[funnymonkey92]

Homework Statement

an adult is pulling two small children in a sleigh over level snow. The sleigh and children have a total mass of 47kg. The sleigh rope makes an angle of 23 degrees with the horizontal. The coefficient of kinetic friction between the snow and the sleigh is 0.11. Calculate the magnitude of the tension in the rope needed to keep the sleigh moving at a constant velocity.

Relevant Equations

Fk=μFn
Fg= mg
ƩFx=0
ƩFy=0

 

[kuruman]

The solution set up looks right.

 

[haruspex]

As a matter of style, it is much better to keep everything symbolic until the end. It has many benefits.
E.g. in the present case write
$F\cos(\theta)=(mg-F\sin(\theta))\mu_k$
$F(\cos(\theta)+\sin(\theta)\mu_k)=mg\mu_k$
etc.

 

[berkeman]

@funnymonkey92 -- Welcome to PhysicsForums.

One other tip for posting here is to look through the "LaTeX Guide" link below the Edit window. That will help you to be able to type your work into the forum so that others can quote your work. It also makes it much easier for folks to read your work (images are often too dark and fuzzy to easily read). Learning to write equations in LaTeX is also a good skill in general, since you can use it for your homework and later in your real work.

 

[funnymonkey92]

The solution set up looks right.

Could you please help me with my next steps?

 

[funnymonkey92]

@funnymonkey92 -- Welcome to PhysicsForums.

One other tip for posting here is to look through the "LaTeX Guide" link below the Edit window. That will help you to be able to type your work into the forum so that others can quote your work. It also makes it much easier for folks to read your work (images are often too dark and fuzzy to easily read). Learning to write equations in LaTeX is also a good skill in general, since you can use it for your homework and later in your real work.

I'll try that thank you!

 

[kuruman]

Could you please help me with my next steps?

Look at the right hand side of the last equation. There is F_T multiplying both terms. You can write the right hand side as F_T(something). What is that (something)?

 

[funnymonkey92]

Look at the right hand side of the last equation. There is F_T multiplying both terms. You can write the right hand side as F_T(something). What is that (something)?

F_T cos + sin ?

 

[kuruman]

This is the sum of two terms. It has to be the product of two terms.

 

[funnymonkey92]

This is the sum of two terms. It has to be the product of two terms.

sooo... Ft cos x sin ?

sorry I'm new to the LaTex notation and idk how to put 't' in the subscript like i did before LOL

 

[kuruman]

It's not the LaTeX. It's your algebra skills. Suppose you have 2*3 +2. That's equal to 8. It can also be written as 2*(3+1) which is still 8. Do you see what to do with F_T? Incidentally, if you wish to write this in LaTeX you use the underscore, F_T and sandwich the expression between ## on either side. Also, "cos" and "sin" are meaningless without an angle as an argument.