Magnitude of Single Displacement:

[sonastylol]

[SOLVED] Magnitude of Single Displacement:

Please bear with me, I'm going to try and properly format this, so you forum-goers actually want to help me out.

Homework Statement

A novice golfer on the green takes three strokes to sink the ball. The successive displacements are 7.4 m to the north, 2.8 m northeast, and 9.9 m 79degreeswest of south. Starting at the same initial point, an expert (lucky) golfer could make the hole in a single displacement. What is the magnitude of this single displacement? Answer in units of m.

Homework Equations

Magnitude = $$\sqrt{(axi)^2 + (ayj)^2}$$

The Attempt at a Solution

For this equation:

Magnitude of A: $$\sqrt{(0)^2 + (7.4)^2}$$
Magnitude of B: $$\sqrt{(2.8cos45)^2 + (2.8sin45)^2}$$

Heres the tricky part:
Vector C is described as 9.9m 79 degrees west of south. Does this make it 191 degrees?
If yes: Vector C should be: $$\sqrt{(9.9cos191)^2 + (9.9sin191)^2}$$

I then add up the values of Magnitude A, B, C to get the answer... yes?


Thanks for your time.

 

[Kurdt]

No you don't add the magnitudes to get the final magnitude. You need to find out what direction he should have hit the ball to make it in one shot and then find the magnitude. Try drawing a diagram it will help.

 

[sonastylol]

i don't exactly understand what we are trying to do anymore then.. the answer isn't the addition of the 3 vectors magnitudes?

Is the answer the magnitude of one "new vector?" -- Like if we make a Vector D and give it an x and y component, from the addition of the first 3 vectors?

 

[Kurdt]

Is the answer the magnitude of one "new vector?" -- Like if we make a Vector D and give it an x and y component, from the addition of the first 3 vectors?

That is correct.

 

[sonastylol]

hmmm... I think maybe my angles are wrong.

I did Vector D x-components: 0 + (2.8cos(45)) + (9.9cos(191))
Vector D y-components: 7.4 + (2.8sin(45)) + (9.9sin(191))

The answer ended up being 10.769.Thank you :)