# Projectile motion problem- did I do it right?

1. Sep 29, 2015

### Kingyou123

1. The problem statement, all variables and given/known data
2. Relevant equations
I wrote them down in my attempt at a solution
3. The attempt at a solution
Second upload, 81.48 meters high seems really wrong to me...

#### Attached Files:

File size:
32.8 KB
Views:
56
• ###### 20150929_214123.jpg
File size:
41.9 KB
Views:
53
2. Sep 29, 2015

### Student100

As an aside, looking at your work is hard to follow. I think you could work on your organizational skills and hold off a bit more before plugging in numbers.

Your height at 95 meters downrange is incorrect, why don't we break this problem into segments. What are you trying to find initially to solve this problem?

3. Sep 30, 2015

### RUber

Since the launch angle is 45 degrees, you can make use of the fact that vx = vy for the components of initial velocity.

4. Sep 30, 2015

### haruspex

The formula you quote at the end of line 6 (d= etc.) is only valid when there is no net vertical displacement.
I heartily endorse Student100's advice to avoid plugging in numbers until the very end. Work the algebra entirely symbolically. Much easier to follow, to check for dimensional consistency, to spot algebraic mistakes....