Ball dropped from building - find speed and kinetic energy

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SUMMARY

A 0.50 kg mass dropped from a 20 m tall building reaches a final speed of 14 m/s just before hitting the sidewalk, calculated using the formula vf = √(2 * g * h), where g is 9.8 m/s² and h is the height. The kinetic energy (KE) of the ball halfway down can be determined using the equation KE = 0.5 * m * v², where v is the speed at that point. The discussion confirms the conservation of energy principle, emphasizing the relationship between potential energy and kinetic energy during free fall.

PREREQUISITES
  • Understanding of gravitational acceleration (9.8 m/s²)
  • Familiarity with the equations of motion for free fall
  • Knowledge of kinetic energy formula (KE = 0.5 * m * v²)
  • Basic algebra skills for manipulating equations
NEXT STEPS
  • Study the derivation of the equations of motion for free-falling objects
  • Learn about energy conservation principles in physics
  • Explore the concept of potential energy and its relationship with kinetic energy
  • Investigate real-world applications of free fall in engineering and safety design
USEFUL FOR

Students in physics, educators teaching mechanics, and anyone interested in understanding the principles of motion and energy conservation in free fall scenarios.

NewJersey
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An 0.50kg mass is droped from the top of a 20m tall building. Immediately before hitting the sidewalk

a) the speed of the ball is ?
b) The KE of the ball half way down will be


Help??
 
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What's being conserved here, and what equation should you use? Any thoughts?
 
Basically right now I am at this point
vf= (2*9.8* 20) the sqaure root of this answer .

Would that tell me the final speed
 
Yes, that is correct.
 
So for part b

vf= 2*9.8*10 and the sqaure root of this
= 14

Is this part right.
 
Well, that is the speed that you would plug into the equation for kinetic energy, but yes, you are correct.
 

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