The work energy principle and power

In summary, the work-energy principle states that the work done on an object is equal to the change in its kinetic energy. Power, on the other hand, is the rate at which work is done or energy is transferred. The work-energy principle and power are closely related, as power is a measure of how quickly work is being done. Real-world examples of the work-energy principle can be observed in everyday situations such as pushing a shopping cart, dropping an object, and a car accelerating. This principle can be applied to all forms of energy and is a fundamental concept in physics. It is closely related to the conservation of energy, and can be used to solve problems and make predictions in physics.
  • #1
Shah 72
MHB
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0
A box of mass 25kg is pulled 5m across a smooth floor by rope with tension 22N. The rope is inclined at 40 degree to above the horizontal. There is a frictional force with average value 12N. The box starts from rest. Find the final speed.
Iam getting the ans 1.97m/s.
The textbook ans is 1.39 m/s
Pls help
 
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  • #2
$W_{net} = [22\cos(40) - 12]\cdot 5 = \dfrac{1}{2} \cdot 25 \cdot v_f^2 \implies v_f = 1.39 \, m/s$
 
  • #3
skeeter said:
$W_{net} = [22\cos(40) - 12]\cdot 5 = \dfrac{1}{2} \cdot 25 \cdot v_f^2 \implies v_f = 1.39 \, m/s$
Thank you!
 

FAQ: The work energy principle and power

1. What is the work-energy principle?

The work-energy principle states that the work done on an object is equal to the change in its kinetic energy. This means that the amount of work done on an object will result in a change in its speed or direction.

2. How is work calculated?

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

3. What is the relationship between work and energy?

Work and energy are closely related, as work is the transfer of energy from one form to another. When work is done on an object, energy is either added or removed from the object, resulting in a change in its energy state.

4. How is power related to the work-energy principle?

Power is the rate at which work is done or energy is transferred. It is calculated by dividing the work done by the time it takes to do the work. This means that the more work is done in a shorter amount of time, the greater the power.

5. Can the work-energy principle be applied to all types of energy?

Yes, the work-energy principle can be applied to all forms of energy, including kinetic, potential, thermal, and electrical energy. This is because all forms of energy can be converted into work or vice versa.

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