# Homework Help: Work problem

1. Nov 18, 2007

### rhxoehwhfh

Tony pulls his wagon a distance of 15 m across the garden while applying a force of 160 N on the wagon’s handle. If the handle makes an angle of 40degree with the horizontal, how much work did Tony do on the wagon?

I have an idea that W= F*D but why does question have the fact that handle makes an angle horizantal 40 degree angle?...

2. Nov 18, 2007

### Astronuc

Staff Emeritus
Because one is looking for the work applied in the direction of travel (and parallel with the horizontal). The force at an angle has horizontal and vertical components. Only the force parallel to travel is doing the work. The normal force is static since the wagon is not gaining elevation in the gravity field.

3. Nov 18, 2007

### rhxoehwhfh

so degrees doesnt affect the amount of work?...

4. Nov 18, 2007

### rhxoehwhfh

does anyone know this problem??

5. Nov 18, 2007

### rock.freak667

You have to resolve the force into vertical and horizontal components. the component that is in the same direction as the force you call that $F_1$ and then you use the formula $W=F_1s$ where s is the displacement IN THE DIRECTION OF THE FORCE.

yes the angle at which the force acts varies that amount of work that it does

6. Nov 18, 2007

### Astronuc

Staff Emeritus
Resolve the force into vertical and horizontal components.

Using the angle $\theta$ with respect to horizontal, FH = F cos$\theta$, which is the force doing the work,

and vertical, FV = F sin$\theta$

or x (horizontal) and y (vertical).

If one does F*d, where * implies the dot product of the force vector and the displacement vector, then the cos of the angle is part of the solution. The dot product means one is applying the component of force parallel with the direction of displacement.

Last edited: Nov 18, 2007
7. Nov 18, 2007

thank you