Forces and kinetic energy problem

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SUMMARY

The discussion focuses on calculating Shawn's kinetic energy while riding his bike, which has a total mass of 43.5 kg. The problem involves converting distance from kilometers to meters and time from minutes to seconds to determine average velocity, calculated as approximately 2.08333 m/s. The kinetic energy formula, KE = 1/2 * m * v^2, is applied, resulting in a calculated kinetic energy of 45.3124 J, which differs from the expected answer of 94.4014 J. The discrepancy highlights the importance of correctly applying the kinetic energy formula.

PREREQUISITES
  • Understanding of basic physics concepts, specifically kinetic energy.
  • Familiarity with the formula KE = 1/2 * m * v^2.
  • Ability to convert units (kilometers to meters, minutes to seconds).
  • Knowledge of average velocity calculations using avgV = x/t.
NEXT STEPS
  • Study the derivation and applications of the kinetic energy formula.
  • Learn about unit conversions in physics, focusing on distance and time.
  • Explore problems involving average velocity and its implications in motion.
  • Investigate the relationship between mass, velocity, and kinetic energy in various contexts.
USEFUL FOR

This discussion is beneficial for physics students, educators, and anyone interested in understanding the principles of kinetic energy and motion calculations.

kza62
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Homework Statement


Shawn and his bike have a total mass of 43.5 kg. Shawn rides his bike 1.3 km in 10.4 min at a constant velocity.
The acceleration of gravity is 9.8 m/s^2
What is Shawn's kinetic energy?


Homework Equations


F = ma
Ff = u * Fn
Fn = mg
avgV = x/t
x = 1/2(Vf + Vi)t


The Attempt at a Solution



ok so I converted km to m and min to s:
x = 1300m
t = 624s
and then i used avgV = x/t so avgV = ~2.08333 m/s

i have no idea what kinetic energy is, this hasn't been covered in class yet but I wanted to get ahead because I think I am coming down with the flu. The answer to the problem is supposed to be 94.4014 J but I have no idea how to set this problem up to get this. Please help me! Thanks.
 
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The kinetic energy = 1/2*m*v^2
 
THAAATTSS what i needed ooohhh maaann thanks rl.bhat!
so it would be (0.5)(43.5)(2.08333)^2 = 45.3124 J

thanks again!
 

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