Advertisements
Advertisements
Questions
State the S.I. unit of power.
Advertisements
Solution
Electric power is the rate at which an electric circuit transfers electrical energy per unit of time.
The SI unit of power is the watt, one joule per second
`P = "work"/"time in Secs" = w/t`
APPEARS IN
RELATED QUESTIONS
Give reasons for the following A teacher moving around in the class is doing work but a child standing and reading a book is not doing any work.
A person of mass 50 kg climbs a tower of height 72 metres. Calculate the work done. (g = 9.8 m s−2).
Name the force acting away from the centre of circular path.
A man lifts a mass of 10 kg from the floor to a shelf 4 meter high. If g = 10 ms-2, what is the work done?
No work is done by a man moving on a horizontal road while carrying a box on his head. Explain.
A block of mass 20 kg is pulled up a slope (fig.12) with a constant speed by applying a force of 500 N parallel to the slope. A and B are initial and final positions of the block.
(a) Calculate the work done by the force in moving the block from A and B.
(b) Calculate the potential energy gained by the block.
Fill in the boxe to show the corresponding energy transformation.
(i) A 200g ball is thrown vertically upward with an initial velocity of 30 ms-1. Draw a velocity-time graph for the motion of ball.
(ii) How long will the ball take to reach the highest point?
(iii) What will be the kinetic energy of ball, when it returns to the starting point, neglecting the air resistance?
(iv) What will be the potential energy of ball at highest point?
