Minimum Speed for Cliff Diving to Avoid Ledge: What Equation to Use?

  • Thread starter Thread starter ziddy83
  • Start date Start date
  • Tags Tags
    Physics Velocity
Click For Summary
SUMMARY

The discussion focuses on calculating the minimum horizontal speed required for a swimmer to safely clear a ledge while diving off a cliff. The cliff is 9.00 meters high, and the ledge is 1.75 meters wide. To find the initial velocity, participants recommend using the equations of motion for both the vertical (y) and horizontal (x) components. Specifically, the vertical motion equation is set to y = -9, while the horizontal motion equation is set to x = 1.75, allowing for the elimination of time (t) to solve for the initial velocity (v).

PREREQUISITES
  • Understanding of basic physics concepts, particularly projectile motion.
  • Familiarity with the equations of motion in two dimensions.
  • Ability to manipulate algebraic equations to isolate variables.
  • Knowledge of horizontal and vertical motion components in physics.
NEXT STEPS
  • Study the equations of motion for projectile motion in detail.
  • Learn how to derive and manipulate equations for horizontal and vertical components.
  • Explore real-world applications of projectile motion in sports and engineering.
  • Investigate the effects of air resistance on projectile motion calculations.
USEFUL FOR

This discussion is beneficial for physics students, educators, and anyone interested in understanding the dynamics of projectile motion, particularly in sports science and engineering contexts.

ziddy83
Messages
87
Reaction score
0
Ok, here is the question.

A swimmer dives off a cliff with a running horizontal leap. What must her minimum speed be just as she leaves the top of the cliff so that she will miss the ledge at the bottom which is 1.75 m wide and 9.00m below the top of the cliff.

which equation would i use? I know the x and y components, but i don't know the time or the initial velocity. can anyone help? Thanks
 
Physics news on Phys.org
Yes, you don't know the initial velocity- that's what you are asked to find. You also don't know the time (at which she passes the ledge) so you have two "unknowns". To solve that you need two equations- which you have!

Write out the equation for the height (y component) as a function of time (it's simpler if you take both initial x and initial y as 0). She passes the cliff when she is 9 m below the cliff: set the formula for y = -9. She must be at least 1.75 m from the cliff horizontally: set the formula for x= 1.75. Solve these two equations for v and t.
(The question only asks for v. If you can solve for v by eliminating t, you don't need to then solve for t.)
 
Excellent...thanks.
 

Similar threads

Replies
7
Views
2K
Replies
3
Views
3K
  • · Replies 3 ·
Replies
3
Views
16K
  • · Replies 1 ·
Replies
1
Views
1K
  • · Replies 3 ·
Replies
3
Views
8K
Replies
1
Views
3K
Replies
2
Views
3K
  • · Replies 4 ·
Replies
4
Views
2K
  • · Replies 16 ·
Replies
16
Views
4K
  • · Replies 1 ·
Replies
1
Views
5K