Very quick question regarding work and kinetic energy

In summary, the question asked for the change in kinetic energy given a force applied on a block, a distance, and the work done by friction. To solve, you can add the work done by the applied force and the absolute value of the work done by friction, then equate it to the change in kinetic energy. This approach can also be helpful in solving more complex questions, such as those involving capacitors.
  • #1
almosthavoc
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Homework Statement


The question gave a force applied on a block as well as a distance. It also gave the work done by friction which was negative. The question was to find the change in kinetic energy.

Homework Equations


Wnet = change in KE

The Attempt at a Solution


I found the work done by the applied force which is just Fd. Frictional force was already given. My question is do I simply add the 2 works (essentially subtracting from the work done by the applied force) or do I add the absolute value of both?
 
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  • #2
In questions such as this using this is helpful to think

Energy given (Fd) = energy gained(change in kinetic or potential energy ) + energy lost as heat( in this case absolute value of work by friction)

Now this question is really simple so you can just calculate the total Work by numerically adding Work done by Applied force and friction (essentially subtracting), and then equating to change in K.E, But there are problems (For Example related to capacitors) where thinking like this is very intuitive and fast.
 

1. What is work and kinetic energy?

Work is the measure of the amount of force applied to an object over a certain distance. Kinetic energy is the energy an object possesses due to its motion.

2. How are work and kinetic energy related?

Work and kinetic energy are directly related. The work done on an object is equal to the change in kinetic energy of that object.

3. How is work calculated?

Work is calculated by multiplying the force applied to an object by the distance over which the force is applied. The formula for work is W = Fd.

4. What is the unit of measurement for work and kinetic energy?

The unit of measurement for work and kinetic energy is the joule (J). One joule is equal to one newton-meter (N⋅m).

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

Some real-life examples of work and kinetic energy include pushing a shopping cart, throwing a ball, and riding a bicycle. In each of these examples, work is being done to transfer energy and cause an object to move.

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