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(i) The conversion of part of the energy into an undesirable form is called ______________.
(ii) For a given height h, __________________ the length l of the inclined plane, lesser will be the effort required.
Concept: Forms of Energy > Solar Energy
An electron emitter must have _____________ work function and ___________ melting point.
Concept: Concept of Work
A man having a box on his head, climbs up a slope and another man having an identical box walks the same distance on a levelled road.
Who does more work against the force of gravity and why?
Concept: Work Done by the Force of Gravity (W = mgh)
How is the unit horsepower related to the S.I. unit of power?
Concept: Work Done by the Force of Gravity (W = mgh)
State the energy changes in the following case while in use:
An electric iron
Concept: Conversion of Energies
State the energy changes in the following case while in use:
A ceiling fan
Concept: Conversion of Energies
Name the unit of physical quantity obtained by the formula `(2K)/v^2` Where K: kinetic energy, v: linear velocity
Concept: Mechanical Energy > Kinetic Energy (K)
Derive a relationship between S.I. and C.C.S. unit of work
Concept: Concept of Work
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?
Concept: Concept of Work
Name the physical quantity measured in terms of horse power.
Concept: Forms of Energy > Solar Energy
What is a solar cell?
Concept: Forms of Energy > Solar Energy
Two bodies have masses in the ratio 5 : 1 and their kinetic energies are in the ratio 125 : 9. Calculate the ratio of their velocities.
Concept: Mechanical Energy > Kinetic Energy (K)
A body of mass 10 Kg is kept at a height of 5m. It is allowed to fall and reach the ground.
(i) What is the total mechanical energy possessed by the body at the height of 2m assuming it is a frictionless medium ?
(ii) What is the kinetic energy possessed by the body just before hitting the ground ? Take g = 10 m/s2.
Concept: Principle of Conservation of Energy
Concept: Concept of Power
A body is thrown vertically upwards. Its velocity keeps on decreasing. What happens to its kinetic energy as its velocity becomes zero?
Concept: Forms of Energy > Solar Energy
When the speed of a moving object is doubled, then its kenetic energy ______.
Concept: Mechanical Energy > Kinetic Energy (K)
The energy conversion in a washing machine is from ______.
Concept: Conversion of Energies
What should be the angle between the direction of force and the direction of displacement, for work to be negative?
Concept: Measurement of Work
Calculate the power spent by a crane while lifting a load of mass 2000 kg, at velocity of 1.5 ms-1. (g = 10 ms-2)
Concept: Concept of Power
A car of mass 120 kg is moving at a speed 18 km/h and it accelerates to attain a speed of 54 km/h in 5 seconds. Calculate:
- the work done by the engine.
- the power of the engine.
Concept: Mechanical Energy > Kinetic Energy (K)
