When a light and a heavy body have equal K.E, then which one has a greater momentum?
In SI system, the unit of P.E. is
Kilowatt hour (kWh) represents the unit of
The kilowatt-hour (SI symbol: kW⋅h or kW h; commonly written as kWh) is a unit of energy equal to 3600 kilojoules (3.6 megajoules). The kilowatt-hour is commonly used as a billing unit for energy delivered to consumers by electric utilities.
When speed of a motor car increases six times, then kinetic energy increases by
Let initial speed of the car be v m/s and mass be m kg
Using the equation
K.E.= (mv²) / 2
It can be observed that, if we increase the speed (v) by 6 times the kinetic energy will increase by 36 times.
1 kWh equals
When speed of the moving object is doubled its
When time taken to complete a given amount of work increases, then
When the force applied and the displacement of the body are inclined at 90° with each other, then work done is
The KE. of a body in increased most by doubling its
If a force F is applied on a body and it move with velocity v, then power will be :-
Work done by a centripetal force
Potential energy and kinetic energy are types of
Mechanical energy is the energy that is possessed by an object due to its motion or due to its position. Mechanical energy can be either kinetic energy (energy of motion) or potential energy (stored energy of position).
Work done in moving a 50 kg block through a horizontal distance of 10 m by applying a force of 100N which makes an angle of 60° with the horizontal is
We know, work done :-
W = FS cos theta
Here, F = 100 , S = 10 , theta = 60°
So, W = 100 * 10 * cos 60°
W = 500 J
kWh is the unit of
An elevator is designed to lift a load of 1000 kg through 6 floors of a building averaging 3·5 m per floor in 6 sec. Power of the elevator, neglecting other losses, will be
Total height, h = 6 x 3.5 = 21 m
So total work done, W = mgh = 1000 x 9.8 x 21 = 205800J
Power, P = W/t = 205800 / 6 = 3.43 x 104 watt
The work done by a body is directly proportional to :
Work done is said to be positive when a force causes displacement:
The work done on an object does not depends on the
In which case work is not done:
In which case work is done:
A stone is tied to a string and whirled in a circular path. The work done by the stone is :
In order to do work, energy is
A rocket rises up in the air due to the force generated by the fuel. The work done by the:
As the rocket moves in the direction of force generated by fuel, therefore it is positive work. As the force of gravity acts in the direction opposite to the displacement. Therefore, it is negative work.
One joule work is said to be done when a force of one newton acts through a distance of:
Work is the product of time and: