• Support PF! Buy your school textbooks, materials and every day products Here!

Understanding Projectiles (Example Problem Given)

  • #1
I dont know how to tackle projectiles and would like to have someone sort of show me what you look for in projectiles and how you normally tackle projectile problems.

The golfer wants to hit the ball the same horizontal distance of 130M and 20M above his tee-off point as in Problem 10-32, but in this case, the tee-off point is 10M above the landing spot of the ball. What is the ball's initial velocity.

*10-32 just states the same problem but doesnt have a 10M tee-off point*


Im using the 3 kinematic formulas.

S= VoT + 1/2at²
V=Vo + at
V²=Vo² + 2as

I just dont know where to begin other then to draw a diagram. I understand somewhere in this problem I must use trig functions cos, sin but im seriously stuck here..How do you guys normally tackle these projectile problems...break it down like im a 1st grader!
 

Answers and Replies

  • #2
Delphi51
Homework Helper
3,407
10
I have yet to see one that doesn't yield to the basic high school approach.
Make two headings for HORIZONTAL and VERTICAL. Under horizontal, write d = vt. Under vertical write V = Vi + at and d = Vi*t + .5*a*t².
Usually you only use two of the equations, but you don't know in advance which two, so you put the knowns into all three and then take a look. Sometimes you have to solve two of them as a system of equations.

In this particular example, there appear to be an infinite number of solutions. If you shoot at 45 degrees, there is a speed v1 that works. If you shoot a little lower or higher, a slightly larger speed is needed. And so on.
 

Related Threads on Understanding Projectiles (Example Problem Given)

  • Last Post
Replies
5
Views
796
Replies
6
Views
4K
Replies
2
Views
1K
Replies
3
Views
1K
  • Last Post
Replies
1
Views
17K
Replies
6
Views
1K
Replies
4
Views
992
Top