Work and energy, Physics

WORK AND ENERGY

 

1.  Work can be defined as: the force applied in direction of displacement ×.  This means that if the force F acts at an angle θ with respect to the direction of motion, then 

      →   →

W = F ⋅ d = Fd cosθ

1233_work energy.png

2.  a) Work is the scalar quantity - it has magnitude but no direction.

b) The dimensions of the  work are: M × (L T -2 ) × =  M L2T -2

 

c) The units: 1 Newton × 1 Metre =  1 Joule (J)

 

3.  Suppose you lift the mass of 20 kg from a distance of 2 metres. Afterwards the work you perform is 20 kg × 9.8 Newtons × 2 metres  = 39.2 Joules. Conversely, the force of gravity is directed opposite to the force exerted by you and the work done by gravity is - 39.2 Joules.

 

4. What if the force differs with distance (as we pull the spring harder as it becomes longer). In such case, we should break up distance over which the force acts into small parts so that the force is approximately constant over each bit. As we create the pieces smaller and smaller, we will attain the exact result:

0

90_work energy2.png

Now add up all the little pieces of work:

1863_work energy1.png

To get the exact result let Δx → 0 and the number of intervals N

7.  Energy is the capacity of a physical system to perform work:

?    it comes in various forms - mechanical, nuclear, chemical, electrical,  etc

1)   it can be stored

2)   it can be converted into different forms

3)    it can never be created or destroyed

Posted Date: 7/26/2012 2:42:56 AM | Location : United States







Related Discussions:- Work and energy, Assignment Help, Ask Question on Work and energy, Get Answer, Expert's Help, Work and energy Discussions

Write discussion on Work and energy
Your posts are moderated
Related Questions
in need of projects on '' PHYSICS OF THE BRAIN''. Thanks

Q. Explain about end rule? When glanced from one end if the current through the solenoid is along clockwise direction the nearer end corresponds to South Pole and the other end

Total height of the gymnast just before falling back down is=(2+.3)=2.3m Energy gained at that point = m*g*h(m=mass, g=gravitational force, h=height) =55*9.8*2.3=1239.7 J

Q. What is a fuse wire? i) Fuse wire is an alloy of lead 37% as well as tin 63%. It is linked in series in an electric circuit. ii) It has high resistance as well as low mel

Eddington limit (Sir A. Eddington) The theoretical limit on which the photon pressure would go above the gravitational attraction of light-emitting body. i.e., a body emitting


As electric field is conservation, work done and as potential difference among two points is path independent and depends only on the position of points between which the charge is

Using the Maxwell's equation explain that electromagnetic waves transverse in nature.

How many types does heat transfer? There are three ways of heat tranfer. a) Conduction (transfer of heat among objects in direct contact) b) Convection (transfer of he

a.  State the Faraday's laws of electromagnetic induction. b.  A conducting circular loop is placed in an uniform magnetic field B=0.020 T with its plane perpendicular to the fi