Advertisements
Advertisements
Question
A body does 20 J of work in 10 s. What is its power?
Advertisements
Solution
POWER = `"work done"/"time taken" = 20/10` = 2 watt
APPEARS IN
RELATED QUESTIONS
A force acts on a body and displaces it by a distance S in a direction at an angle θ with the direction of the force. What should be the value of θ to get the maximum positive work?
What are the two kinds of mechanical energy?
A body of mass 5 kg falls from a height of 10 m to 4 m. Calculate:
The loss in potential energy of the body,
Fill in the blank with suitable word :
Work is measured as a product of __________ and __________
Write an expression for work done by a force depends?
Give an example
Electrical energy changes of sound energy.
Give an example
Light energy changes to electrical energy.
A man climbs a slope and another walks same distance on level road. Which of the two expends more energy and why?
A truck driver can load oil drums into the back of the truck by pushing them up a sloping plank, or by lifting them directly. Each drum has a mass of 80 kg, the plank is 3 m long, and the back of the truck is 0.8 m above the ground.
(i) How much force would be needed to lift a drum into the truck directly/without using the plank? (Take g = 10 m/s2)
(ii) How much energy would be required in lifting the drum into the truck without the plank?
(iii) If the force needed to push the drum up the plank is 300 N, why is this less than the answer to part (i)?
(iv) When the truck is loaded, the driver drives off. List the major energy changes that take place in moving the truck.
(v) The driver has to stop at the factory gates. What happens to the kinetic energy of the truck?
