# Projectile motion-range calculation

1. Oct 15, 2014

### Apleo

• Warning! Posting template must be used for homework questions. Effort must be shown in the Attempt at a Solution.
1. the surface of a hill is inclined at α to horizontal,a stone is thrown from the top of the hill at initial speed u at angle β with vertical line. How far from the top will the stone strike the ground?

2. R=(u^2 sin2θ)\g or by rotational co ordinate geometry

3. can't prove that the dist covered by the stone is 2(u^2 sinβcos(α-β))\gcos^2 α

2. Oct 15, 2014

### Staff: Mentor

How did you go about trying to solve this? Where is your labelled diagram ?

The provided answer is correct, it's the distance measured along the sloping ground

Last edited: Oct 15, 2014
3. Oct 15, 2014

### Apleo

shall i send you a labelled diagram

4. Oct 15, 2014

### Apleo

How shall i start the calculation?

5. Oct 15, 2014

### Staff: Mentor

Attach a jpeg to your forum post.

6. Oct 15, 2014

### Apleo

the curve of projectile is not perfect.....if you cannot understand please ask! AND sorry for late reply!

#### Attached Files:

• ###### Projectile motion.jpg
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7. Oct 15, 2014

### Staff: Mentor

The launch velocity can be shown resolved into 2 components.

The time taken to cover distance CB can be established.

8. Oct 15, 2014

### Apleo

i had tried but got stuck!

9. Oct 15, 2014

### Staff: Mentor

Show the working of your attempt.

10. Oct 15, 2014

### Apleo

i had got confused with it because the projectile had exceeded its range so i can't solve it , i just checked mine calculation its wrong so suggest me how to start!

11. Oct 15, 2014

### Staff: Mentor

It has to be worked using algebra, as no numerical data is provided.

Can you resolve the launch velocity into vert and horiz components?

Using your diagram, CB is the horizontal distance the projectile travels, because after travelling for that time & distance it hits terrain.

12. Oct 15, 2014

### Apleo

yes i had resolved it into vert & hoz components...........but after that what should i do?

13. Oct 15, 2014

### Staff: Mentor

"
Well, what is your answer---how do you express the components of its initial velocity?

Last edited: Oct 15, 2014