# Thread: Vector word problem about inclined plane

1. ## Vector word problem about inclined plane

here is the exact problem. i can't figure out how to begin solving it. i just don't see it

A car is being towed up an inclined plane making an angle of 18 degrees with the horizontal. Find the force F needed to make the component of F parallel to the ground equal to 5250 pounds.

2. ## Re: Vector word problem about inclined plane

Originally Posted by CoffeeBird
here is the exact problem. i can't figure out how to begin solving it. i just don't see it

A car is being towed up an inclined plane making an angle of 18 degrees with the horizontal. Find the force F needed to make the component of F parallel to the ground equal to 5250 pounds.
Draw a sketch.

If I understand your question correctly the force F denotes the weight of the car(?).

You are dealing with similar right triangles. So you can use proportions and Pythagorean theorem.

3. ## Re: Vector word problem about inclined plane

that's exactly how it's worded in the book. i'm still lost.

4. ## Re: Vector word problem about inclined plane

Originally Posted by CoffeeBird
that's exactly how it's worded in the book. i'm still lost.
so am I ... what is the angle of the incline?

5. ## Re: Vector word problem about inclined plane

Originally Posted by skeeter
so am I ... what is the angle of the incline?

is it the 18 degrees?

6. ## Re: Vector word problem about inclined plane

Originally Posted by CoffeeBird
is it the 18 degrees?
1. I've marked the 2 similar right triangles.

red = 5250 lbs

2. In the orange triangle you know:

$\displaystyle{\frac{red}{green} = \cos(18^\circ)~\implies~green = \frac{red}{\cos(18^\circ)}}$

3. In the green triangle you know:

$\displaystyle{\frac{green}{weight} = \sin(18^\circ)~\implies~weight = \frac{green}{\sin(18^\circ)}}$

4. Combine both equations to get the weight.