Advertisements
Advertisements
प्रश्न
Explain why, the tip of a sewing needle is sharp.
Advertisements
उत्तर
The tip of a sewing needle is sharp because the area under the pointed end of the sharp needle is very small. Pressure exerted by a sharp needle is more on the cloth and can pierce easily through the cloth.
APPEARS IN
संबंधित प्रश्न
A ball is thrown vertically upwards with a velocity of 49 m/s. Calculate
- the maximum height to which it rises.
- the total time it takes to return to the surface of the earth.
State whether the following statement is true or false :
A falling stone also attracts the earth.
Explain what is meant by the equation :
`g= Gxxm/r^2`
where the symbols have their usual meanings.
Give reason for the following :
The force of gravitation between two cricket balls is extremely small but that between a cricket ball and the earth is extremely large.
Solve the problem.
If the mass of a planet is eight times the mass of the Earth and its radius is twice the radius of the Earth, what will be the escape velocity for that planet?
What will be the weight of a person on earth, who weighs 9N on the moon?
The acceleration produced in a body by a force of given magnitude depends on
Write scientific reason.
The value of gravitational acceleration (g) is taken to be -g when studying the motion of an object thrown upwards in a straight line.
Distinguish between:
Universal gravitational constant - Gravitational acceleration of earth.
Calculate the escape velocity on the surface of the moon given the mass and radius of the moon to be 7.34 × 1022 kg and 1.74 × 106 m respectively.
(Given: G = 6.67 × 10-11 Nm2/kg2)
