Understanding work and kinectic energy?

In summary, the conversation is about understanding the relationship between work, force, acceleration, and kinetic energy in the context of mechanical physics. The individual is trying to understand why kinetic energy is equal for two objects with different masses but the same force applied, and wonders if friction affects this relationship.
  • #1
kyin01
47
0
Hi everyone! So I am taking mechanical physics right now (calc based) and I seem to have a bit of trouble understanding work / kinetic energy.

Homework Statement


1-10.png



Homework Equations


[tex]\vec{F}[/tex]=m[tex]\vec{a}[/tex]

Kinetic energy= [tex]\frac{mv^{2}}{2}[/tex]

Work[tex]_{net}[/tex] = [tex]\Delta[/tex] [tex]\frac{mv^{2}}{2}[/tex]


The Attempt at a Solution


Okay so first, my understanding is like this, please correct me if I am thinking about it the wrong way. [tex]\vec{F}[/tex]=m[tex]\vec{a}[/tex] so if the same amount of force is applied to both and one has a different mass from the other, than acceleration is different and thus velocity is different.
With that said I knew that velocity is different, but why should the kinetic energy be equal?
Can't we have a situation where the velocity is changed to the point where if we plug our two velocities and our different masses in the [tex]\frac{mv^{2}}{2}[/tex] equation the kinetic energy will not be equal?


Now here is where I get lost, my thinking was when there is friction. In the problem it says no friction. If no friction shouldn't the velocity be the same for both masses when the same force is applied? because there is no fiction force to oppose it?


So I am kinda lost as how to understand the way kinetic energy work.
Thanks for your time.
 
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  • #2
[tex]Fd=W=\frac{1}{2}mv^2=KE[/tex]

If the same amount of force is needed to push two objects of different masses an equal distance, then both objects will have equal kinetic energies, albeit different velocities for the two objects if the kinetic energies between the two objects are to be the same.
 
  • #3
So work = kinetic energy?
Ah, that makes a little more sense

i was thinking kinetic energy is the change in work
 
  • #4
Whoops, my mistake. It is. However, your initial is 0 and your final is equal to (1/2)mv^2.
 

1. What is work?

Work is the amount of energy transferred when a force is applied to an object and it causes the object to move in the direction of the force.

2. How is work calculated?

Work is calculated by multiplying the force applied to an object by the distance the object moves in the direction of the force. This can be expressed as W = F x d, where W is work, F is force, and d is distance.

3. What is kinetic energy?

Kinetic energy is the energy an object possesses due to its motion. It is dependent on the mass and velocity of the object.

4. How is kinetic energy related to work?

Kinetic energy and work are related through the Work-Energy Theorem, which states that the work done on an object is equal to the change in its kinetic energy. This means that work can increase or decrease an object's kinetic energy.

5. What are some real-life examples of work and kinetic energy?

Some examples of work and kinetic energy in everyday life include pushing a shopping cart, throwing a ball, riding a bike, and running. In each of these situations, work is being done and kinetic energy is being transferred and transformed.

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