What is weightlessness? Explain with examples.
(N/A) Weightlessness is a state in which the apparent weight of a body becomes zero. This occurs when a body is in a state of free fall,meaning the only force acting on it is gravity,and there is no normal reaction force from any surface.
Examples:
$(i)$ Free-falling lift: When a lift falls freely under gravity,its acceleration $a = g$. The apparent weight $W$ of a person of mass $m$ inside the lift is given by $W = m(g - a)$. Substituting $a = g$,we get $W = m(g - g) = 0$. Thus,the person experiences weightlessness.
$(ii)$ Satellites: An orbiting satellite is in a state of continuous free fall towards the Earth. The centripetal acceleration required for its orbit is provided by gravity $(a_c = g')$. Since the satellite and everything inside it are accelerating at the same rate towards the center of the Earth,there is no normal force between the objects and the floor of the satellite,leading to a state of weightlessness.
Examples:
$(i)$ Free-falling lift: When a lift falls freely under gravity,its acceleration $a = g$. The apparent weight $W$ of a person of mass $m$ inside the lift is given by $W = m(g - a)$. Substituting $a = g$,we get $W = m(g - g) = 0$. Thus,the person experiences weightlessness.
$(ii)$ Satellites: An orbiting satellite is in a state of continuous free fall towards the Earth. The centripetal acceleration required for its orbit is provided by gravity $(a_c = g')$. Since the satellite and everything inside it are accelerating at the same rate towards the center of the Earth,there is no normal force between the objects and the floor of the satellite,leading to a state of weightlessness.
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Similar Questions
$A$ man of mass $70 \; kg$ stands on a weighing scale in a lift which is moving:
$(a)$ Upwards with a uniform speed of $10 \; m s^{-1}$.
$(b)$ Downwards with a uniform acceleration of $5 \; m s^{-2}$.
$(c)$ Upwards with a uniform acceleration of $5 \; m s^{-2}$.
What would be the readings on the scale in each case?
$(d)$ What would be the reading if the lift mechanism failed and it hurtled down freely under gravity?
$(a)$ Upwards with a uniform speed of $10 \; m s^{-1}$.
$(b)$ Downwards with a uniform acceleration of $5 \; m s^{-2}$.
$(c)$ Upwards with a uniform acceleration of $5 \; m s^{-2}$.
What would be the readings on the scale in each case?
$(d)$ What would be the reading if the lift mechanism failed and it hurtled down freely under gravity?
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View SolutionAn object of mass $5\, kg$ is attached to the hook of a spring balance and the balance is suspended vertically from the roof of a lift. The reading of the spring balance when the lift is going up with an acceleration of $0.25\, m/s^2$ is ......... $N$ $(g = 10\, m/s^2)$
Medium
View SolutionAn elevator car,whose floor-to-ceiling distance is $2.7 \, m$,starts ascending with a constant acceleration of $1.2 \, m/s^2$. $2 \, s$ after the start,a bolt begins falling from the ceiling of the car. The free-fall time of the bolt is ......... $s$.
Medium
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