Projectile Motion -- mountain jumper

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SUMMARY

The discussion focuses on a projectile motion problem involving a jumper who runs off a 910-meter cliff at a speed of 4.0 m/s and falls until reaching 150 meters above the valley floor before deploying a parachute. The key equations discussed include the kinematic equation Y = y_0 + v_0t + 1/2*at^2, where y_0 is the initial height of 910 meters, v_0 is the initial vertical velocity (0 m/s), and a is the acceleration due to gravity (-9.8 m/s²). The jumper's time in free fall and horizontal distance from the cliff when the parachute opens are the primary calculations needed to solve the problem.

PREREQUISITES
  • Understanding of kinematic equations in physics
  • Knowledge of projectile motion concepts
  • Familiarity with vertical and horizontal motion components
  • Basic grasp of gravitational acceleration (9.8 m/s²)
NEXT STEPS
  • Calculate the time of free fall using the equation Y = y_0 + v_0t + 1/2*at^2
  • Determine the horizontal distance traveled using the jumper's speed and time of free fall
  • Explore the effects of air resistance on projectile motion
  • Study advanced projectile motion scenarios, including varying launch angles
USEFUL FOR

This discussion is beneficial for physics students, educators, and anyone interested in understanding the principles of projectile motion and free fall dynamics.

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1. Homework Statement
A jumper runs horizontally off a 910 meter mountain with speed 4.0 m/s and enjoys a free fall until she is 150 meters above the valley floor, at which time she opens her parachute. Ignore air resistance

Homework Equations


A) how long is the jumper in free fall.

B) how far from the cliff is the jumper when she opens her parachute?

The Attempt at a Solution


My attempt is attached with kinematic equations. I want to use Y to find time.

I'm confused on Y. Is it the height 910 meters or 910 meters - 150 meters = 760 meters. Can you explain the vertical component to me?
 

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In the case of Y = y_0 + v_0t + 1/2*at^2, your Y at the time you are interested in should be Y at the end of the free fall, or 150m.
y_0 is the starting height, v_0 is the vertical component of initial velocity (zero) and a should be -9.8m/s^2.
 
Thank you RUber. I am about to rework it.
 

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