# JEE Main Work, Energy and Power Revision Notes

View Notes

## JEE Main Work, Energy and Power Revision Notes - PDF Download

When a constant force F is applied on the box upon the smooth surface, at a certain point of application, it offers a displacement s.

Mathematically, it can express as W = F s cos Θ

Here,

Θ = the angle between F and s (displayed in the above image)

Here, F cos Θ plays an important role in the work done.

• ### Role of Gravity in Work Done

The work done by gravity is said to be negative if an object is moving in an upward direction. The expression for the statement is,

Wg = - m.g.h

Note: Work done is positive when it is falling from certain heights.

• ### Role of Friction in Work Done

A concept is always there in our mind that the force of friction results in a negative work. However, as per the observation, it is concluded that the work done by friction may be zero, positive, negative or zero according to the condition.

• ### Role of  a Variable Force in Work Done

If there is a chance of any alteration or variation of magnitude and direction of a force in a three-dimensional space, the expression can be obtained as a function of the position vector F.

Consider that a force is present in 3 – D space. Also, assume that the force’s magnitude as well as direction changes for some reason.

The coordinates are (x, y, z) for this force F.

We can write the work done formula as

$\overrightarrow{F}$ . $\overrightarrow{ds}$ = dW

1. Why is the Force of Gravity Negative?

It has been proven that acceleration due to gravity is always negative. When an object is in its free-falling state, it has been affected only by gravity, which is - 9.81 m/s2 irrespective of the direction.

2. is the Delivered Power Negative?

According to the research, the total power transported to a circuit is equal to the total power absorbed. It has been proven that the power delivered is a negative quantity and power absorbed is a positive quantity

If we deeply study the laws of conservation of mass, it suggests that the total power of all elements in a circuit results in zero.

3. What Are the Basic Features of the Vedantu Learning Program?

Vedantu offers the study program about the subjects: Physics, Chemistry, Mathematics and Biology. The concept, along with precise question and answer sets, can be helpful to our students in these subjects. We are covering all syllabus that comes under JEE and NEET. The mock tests and practice papers can surely help the students to score more.

4. What Are We Offering in Doubt Clearing Sessions?

Yes, students of Vedantu can clarify their doubts about the specific subjects. Our experts deliver quality solutions to the subjects that we are covering. Students are required to register their names and class on our website and subscribe to our program. After that, they will be provided with PDF materials as well as live classes and doubt clearing sessions.

Do you wish to have an edge over others?