Advertisements
Advertisements
प्रश्न
Calculate the work done by a car against gravity in moving along a straight horizontal road. The mass of the car is 400 kg and the distance moved is 2 m.
उत्तर
The weight of the car (mg) is vertically downward and the car is moving along the horizontal road, so the displacement of the car is in the long horizontal, i.e. angle between them is 90°.
Work done by weight of the car
W = Fs cos 90° = 0 .....(cos 90° = 0)
Hence, the work done by the car against gravity will also be zero.
APPEARS IN
संबंधित प्रश्न
The geostationary orbit of the earth is at a distance of about 36000 km from the earth's surface. Find the weight of a 120-kg equipment placed in a geostationary satellite. The radius of the earth is 6400 km.
When you lift a box from the floor and put it on an almirah the potential energy of the box increases, but there is no change in its kinetic energy. Is it a violation of conservation of energy?
Can the work by kinetic friction on an object be positive? Zero?
Can normal force do nonzero work on an object? If yes, give an example. If no, give reason.
Two springs A and B(kA = 2kB) are stretched by applying forces of equal magnitudes a the four ends. If the energy stored in A is E, that in B isA
A potential barrier of 0.4 V exists across a p-n junction. An electron enters the junction from the n-side with a speed of 6.0 × 105 ms-1. The speed with which the electron enters the p side will be `x/3 xx 10^5 "ms"^-1`, and the value of x is ______.
(Given the mass of electron = 9 × 10-31 kg, the charge on electron = 1.6 × 10-19 C.)
The sign of work done by a force on a body is important to understand. State carefully if the following quantity is positive or negative:
Work done by a man in lifting a bucket out of a well by means of a rope tied to the bucket.
The sign of work done by a force on a body is important to understand. State carefully if the following quantity is positive or negative:
Work done by gravitational force on a man in lifting a bucket out of a well by means of a rope tied to the bucket.
The sign of work done by a force on a body is important to understand. State carefully if the following quantity is positive or negative:
Work done by friction on a body sliding down an inclined plane.
The sign of work done by a force on a body is important to understand. State carefully if the following quantity is positive or negative:
Work done by the resistive force of air on a vibrating pendulum in bringing it to rest.
