Energy, Work & Power (11 of 31) Work Energy Principle, Net Work Done on an Object

TL;DR

Calculation of net work and change in velocity using the work-energy theorem.

Transcript

okay in today's video we are going to do not one but two things we're going to calculate first the net work that is done on that object by all of those forces then we are going to use the network to determine the change in velocity of the object don't switch the channel here we go okay we want to figure out he said the network now you should notice... Read More

Key Insights

• 🧑‍🏭 The net work done on an object can be determined by summing up the work done by each force acting on the object.
• 💦 Forces at right angles to the displacement of the object do not contribute to the net work.
• 💦 The work-energy theorem relates the net work done on an object to its change in kinetic energy.

Questions & Answers

Q: How is net work calculated?

Net work is calculated by adding the work done by each force acting on the object. The formula used is net work = force x distance x cosine(theta).

Q: Why does the normal force and gravitational force do no work on the object?

The normal force and gravitational force are at right angles to the displacement of the object. Since the cosine of 90 degrees is zero, these forces do not contribute to the net work.

Q: How is the change in velocity of the object determined using the work-energy theorem?

The work-energy theorem states that the net work done on an object is equal to the change in its kinetic energy. By rearranging the formula, the final velocity of the object can be calculated as the square root of (2 x work / mass).

Q: What is the final velocity of the object in the given example?

In the example, the final velocity of the object is calculated to be 5.25 meters per second using the work of 75 joules and a mass of 5.5 kilograms.

Summary & Key Takeaways

• The video discusses the calculation of net work done on an object and the change in velocity using various forces.

• Four forces are considered: applied force, friction force, normal force, and gravitational force.

• The net force is greater than zero, indicating acceleration, and the net work is calculated by adding the work done by each force.