Home
Class 9
PHYSICS
Define watt. Express kilowatt in terms o...

Define watt. Express kilowatt in terms of joule per second. A 150 kg car engine develops 500 W for each kg. What force does it exert in moving the car at a speed of 20 m//s ?

Text Solution

Verified by Experts

Power of an agent is said to be 1 watt if it can ferform 1 joule of work in one second, i.e., 1 W = 1J//s.
Also, 1 k W = 1000 = 1000 J//s
Since power developed for each kg is 500 W, total power developed by the engine of 150 kg car, i.e.,
`P =150 xx 500 W = 7.5 xx 10^4 W`
Speed of the car, `upsilon = 20 m//s`
Since power = force xx speed,
`force = (power)/(speed) = (7.5 xx10^4 W)/(20 m//s) = 3.75 xx10^3 N`
Promotional Banner

Topper's Solved these Questions

  • WORK AND ENERGY

    PRADEEP|Exercise Very short Answer Question|21 Videos

  • WORK AND ENERGY

    PRADEEP|Exercise Short Answer Questions 2 marks|10 Videos

  • WORK AND ENERGY

    PRADEEP|Exercise Short Answer Questions|11 Videos

  • SOUND

    PRADEEP|Exercise Model Test (sec - B)|12 Videos

Similar Questions

Explore conceptually related problems

When an automobile moves with constant speed down a highway , most of the power developed by the engain is used to compensate on the car by the air and the road, friction forces exerted on the car by the air and the road. If the power developed by an engine is 175 hp , estimate the total friction force (apporox) acting on the car when it is moving at a speed of 25 m//s . One horsepower equals 746 W .

A motor car is fitted with a convex driving mirror of focal length 20 cm . A second motor car is 6 m away from the driving mirror of the first car. Calculate (i) position of second car as seen in the first car mirror. (ii) if the second car is overtaking the first car at a relative speed of 15 m//s , how will its image be moving and in what direction ?

A machine gun has a mass of 20 kg . It fire 20 gram bullets at the rate of 300 bullets per second at a speed of 250 m//s . What force must be applied on the gun to keep it in position ?

A car weight W is on an inclined road that rises by 100 m over a distance of 1 km and applies a constant frictional force W/20 on the car . While moving uphill on the road at a speed of 10 " m "s^(-1) , the car needs power P . If it needs power P/2 while moving downwill at speed v then value of v is :

A 400kg car attains a speed of 50m/s from rest in 20s. The power developed in the engine will be

A 1580 kg car is traveling with a speed of 15.0 m/s. What is the magnitude of the horizontal net force that is required to bring the car to a halt in a distance of 50.0 m ?