Height of ball bounce with air resistance

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SUMMARY

The discussion centers on calculating the height of a ball bounce considering air resistance. A ball with a mass of 0.7 kg and radius of 0.15 m is dropped from a height of 30 m, with air resistance modeled by the equation F_r = 0.5 * S * ρ * v^2, where S is the cross-sectional area and ρ is the air density. The calculated bounce height, assuming an elastic collision, is 9.15 m. The participant expresses interest in alternative methods to solve the problem using kinematic and potential energy equations, questioning the feasibility due to the velocity dependency of air resistance.

PREREQUISITES
  • Understanding of differential equations and their applications in motion analysis.
  • Familiarity with the concepts of elastic collisions and energy conservation.
  • Knowledge of air resistance modeling, specifically the drag force equation.
  • Basic principles of kinematics and potential energy in physics.
NEXT STEPS
  • Research the application of differential equations in modeling motion with air resistance.
  • Explore the principles of elastic collisions and their impact on energy conservation.
  • Study the derivation and implications of the drag force equation in various contexts.
  • Investigate alternative methods for solving motion problems involving air resistance without differential equations.
USEFUL FOR

Physics students, educators, and anyone interested in understanding the dynamics of motion under the influence of air resistance and elastic collisions.

ajuric
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Homework Statement


Ball with mass of 0.7 kg and radius 0.15 m is dropped from top of the building 30 m tall. Force of air resistance which acts on ball is given with the equation:

F_r = \frac{1}{2} c S ρ v^2

where
c = 0.5
S = r^2 ∏
ρ = 1.29 \frac{kg}{m^3}
v = current speed.

How tall will ball bounce of the ground if we suppose that collision was
elastic?

(Ans: h = 9.15 m)

Homework Equations


Given above.

The Attempt at a Solution


I have solved this with differential equations of motions(which took me quite a lot
of time integrating...) but I'm interested whether this can be solved with equations
for kinematic and potential energy and how?
 
Last edited:
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I don't think so, since energy dissipated by air friction is a function of v and you don't know v unless you solve the diff. eq.
 

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