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प्रश्न
How do you define force? What are the forces acting on a man standing in a lift? If the lift moves down with an acceleration of 2 ms−2, what is the net force on the man if his mass is 50 kg?
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उत्तर
Net force acting on a body is equal to mass into acceleration or we may define force as a push or pull which changes or tends to change the state of rest or of uniform motion in a straight line of the body on which it acts.
The forces acting on a man in a lift are
(i) weight of the man acting vertically downwards,
(ii) the reaction of the floor acting vertically upwards.
In a lift accelerating downwards the net force on the man is
F = m(g – a) = 50(9.8 – 2)
= 50 × 7.8 = 390 N.
संबंधित प्रश्न
Define the term Force?
Give one example in the given cases:-
A force changes the shape of a body
Define Newton (the S.I unit of force)
Complete the following:
1 N = ............kgf (approx)
Newton's second law of motion applicable in all condition is:
(a) `F = (Δp)/(Δt)`
(b) F = ma
(c) `F = M (Δv)/(Δt)`
(d) all three
Two balls of masses in ratio 1 : 2 are dropped from the same height find
a) the ratio between their velocities when they strike the ground and
b) the ration if the forces acting on them during motion.
State the condition when on applying a force, the body has the translational motion.
If we apply force against the direction of motion of the body, then the body will
Give two examples to verify that a force tends to change the static condition of a body.
Mention the two types of forces.
