Advertisements
Advertisements
प्रश्न
उत्तर
APPEARS IN
संबंधित प्रश्न
An object thrown at a certain angle to the ground moves in a curved path and falls back to the ground. The initial and the final points of the path of the object lie on the same horizontal line. What is the work done by the force of gravity on the object?
Work done = Force × ........................................
1 J = ______ calorie.
A boy of mass 40 kg climbs up the stairs and reaches the roof at a height 8 m in 5 s. Calculate:
- the force of gravity acting on the boy,
- the work done by him against the force of gravity,
- the power spent by boy. (Take g = 10 m s-2)
Fill in the blank with suitable word :
Work is measured as a product of __________ and __________
What is the SI unit of work?
Define energy and state the unit of energy and the law of conservation of energy.
A girl of mass 50 kg runs up a flight of 40 steps in 20 seconds. If each step in 20 cm high, calculate the power developed by the girl. (g= 10 ms-2).
Fill in the boxe to show the corresponding energy transformation.
State the energy changes which take place when An electric bulb glows when it is connected to a source of electric current.
Give an example
Electrical energy changes to heat energy.
Is power a scalar or a vector quantity?
Name the material commonly used for the manufacturing of solar cells.
The work done by the heart is 1 Joule per beat. Calculate the power of the heart if it beats 72 times in one
The weights of two bodies are 2.0 N and 2.0 kgf respectively what is the mass of each body?
An electric motor pump is 60% efficient and is rated 2.5 H.P. Calculate the maximum load it can lift through a height of 10m in 8 sec. (1 H.P. = 750 W).
Look at the activity below. Reason out whether or not work is done in the light of your understanding of the term ‘work’.
Suma is swimming in a pond.
