Page 12 - Simplied Force

SIMPLIFIED COURSE ON SEE SCIENCE : CHAPTER- FORCE

21) The probability of getting hurt is more when a man jumps from greatest height, why?

Ans: Force is directly proportional to the acceleration due to gravity (i.e. F ∞ g). If a person jumps front
a certain height, his acceleration goes on increasing towards the earth surface. More the acceleration, with
more force he strikes on the earth surface. Hence, the probability of getting hurt is more when a man
jumps from greatest height.
22) What is gravitation?

Ans: The mutual force of attraction between any two bodies in this universe is called gravitation.

23) What is the effect of gravity on the falling object?

Ans: When an object is falling, gravity provides necessary acceleration on it which is always acting
towards the Centre of the heavenly body.

24) What is the value of acceleration due to gravity at equatorial region of the earth? Write in S.I.
unit?
Ans: The value of acceleration due to gravity at

2
a) Equatorial region:- 9.78 m/s
2
b) Polar region: - 9.83 m/s
2
25) The acceleration due to gravity in the moon is 1.67m/s . What does it mean?
Ans: It means that when the object falls towards the surface of the moon under the action of gravity, the
velocity of the falling object increases at the constant rate of 1.67m/s in each second during its fall if the
air resistance is neglected.
26) What is gravitational field and gravitational field intensity?

Ans: The space around a mass over which it can exert gravitational force on other masses is called the
gravitational field of the mass. The gravitational field intensity at a point in the gravitational field is
defined as the force experienced by unit mass placed at that point.

27) A feather and a coin fall simultaneously on the surface of moon, why?

Ans: There is no air resistance (i.e. no atmosphere) on the surface of moon. If there is no air resistance,
the acceleration produces in the freely falling bodies, whatever their masses, are the same. Therefore, if a
feather and a coin are dropped simultaneously on the surface of moon, their speed increases with the same
rate. As a result they reach the ground together.

28) It is difficult to lift a large stone on the surface of the earth but easy to lift small one, why?

Ans: To lift a load, we need to apply the force equal to the weight of the load. The load of an object
depends on the force of gravity and its mass. The force of gravity is more in the large stone as it has more
mass then in small stone. Due to this, large stone has more load than small stone. As a result, it is difficult
to lift a large stone on the surface of the earth but easy to lift small one.

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