How Does the Kinetic Energy Theorem Apply to Bonny Blair's Skating Problem?

In summary, the conversation discusses the kinetic energy theorem and uses it to calculate the work done by friction on Bonny Blair, a skater who skated 5.00 x 10^2 m with an average speed of 12.92 m/s. Her mass was 55.0 kg and she continued skating freely until her speed decreased to 8.00 m/s. The conversation suggests using the formula \Delta K = WW_{friction}=F_{friction}d\cos{\theta} to find the work done on her, with the net force being equal to her mass multiplied by her acceleration. The method suggested by quasar may be easier to use.
  • #1
Femme06Fatale
14
0
Bonny Blair skated 5.00 x 10^2 m with an average speed of 12.92 m/s. Suppose she corssed the finish line at this speed and then skated freely until her speed was 8.00 m/s. If her was mwas 55.0 kg, how much work was done by friction?

Can anybody explain the kinetic energy theorem or help me work through this problem?
 
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  • #2
The kinetic energy theorem says her variation in kinetic energy is equal to the work done on her.

If you can find by how many Joules her kinetic energy varied, then this same number is equal to the work done on her:

[tex]\Delta K = W[/tex]
 
  • #3
[tex]W_{friction}=F_{friction}d\cos{\theta}[/tex]

[tex]F_{net}=ma[/tex]

Can you figure it out using those (careful what you use for [itex]d[/itex])?
 
  • #4
Oh, yes, quasar's method may be easier.
 

Related to How Does the Kinetic Energy Theorem Apply to Bonny Blair's Skating Problem?

What is the Kinetic Energy Theorem?

The Kinetic Energy Theorem states that the kinetic energy of an object is equal to half of its mass multiplied by the square of its velocity. It is a fundamental principle in physics and is used to understand the motion of objects.

How is the Kinetic Energy Theorem derived?

The Kinetic Energy Theorem is derived from the work-energy theorem, which states that the work done on an object is equal to the change in its kinetic energy. By applying this theorem to a moving object and considering the forces acting on it, we can derive the equation for kinetic energy.

What are the units of kinetic energy?

The units of kinetic energy are joules (J). This is because kinetic energy is a form of energy, and energy is measured in joules.

Can the Kinetic Energy Theorem be applied to all objects?

Yes, the Kinetic Energy Theorem can be applied to all objects, regardless of their size, shape, or composition. As long as an object is in motion, it possesses kinetic energy, and the theorem can be used to calculate it.

How is the Kinetic Energy Theorem useful in real life?

The Kinetic Energy Theorem has many practical applications in everyday life. For example, it is used in sports to understand the motion and energy of players and equipment. It is also used in engineering to design structures and vehicles that can withstand the kinetic energy of moving objects. Additionally, the theorem is used in the study of collisions and the conservation of energy in physics.

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