If a man of mass 50 kg is in a lift moving down with a acceleration equal to acceleration due to gravity, then the apparent weight of the man is:
If a man of mass 50 kg is in a lift moving down with a acceleration equal to acceleration due to gravity, then the apparent weight of the man is:
0
100 N
25 N
5 N
The Correct Option is A
Approach Solution - 1
To solve the problem, we need to determine the apparent weight of a man in a lift that is accelerating downward with an acceleration equal to gravity.
1. Understanding Apparent Weight:
Apparent weight is the normal force exerted by the floor on the person. It is given by the equation:
$ W_{\text{apparent}} = m(g - a) $
where:
$m$ = mass of the man = 50 kg,
$g$ = acceleration due to gravity = 9.8 m/s²,
$a$ = acceleration of the lift = 9.8 m/s² (since it's moving down with acceleration equal to gravity).
2. Substituting the Values:
$ W_{\text{apparent}} = 50 \cdot (9.8 - 9.8) = 50 \cdot 0 = 0 \, \text{N} $
3. Interpretation:
When the lift moves downward with acceleration equal to gravity, the person experiences weightlessness because the normal force becomes zero. This is similar to free fall.
Final Answer:
The apparent weight of the man is 0 N.
Approach Solution -2
The correct option is: (A) 0.
With the provided mass of the boy being m = 50 kg, and as the boy moves downward with an acceleration a = 9.8 m/s², the apparent weight (W_app) can be calculated as:
Apparent Weight = m * (g - a) = 50 * (9.8 - 9.8) = 50 * 0 = 0.
Top TS EAMCET Physics Questions
- A wooden box lying at rest on an inclined surface of a wet wood is held at static equilibrium by a constant force $F$ applied perpendicular to the incline. If the mass of the box is $1\,kg$, the angle of inclination is $30^{\circ}$ and the coefficient of static friction between the box and the inclined plane is $0.2$, the minimum magnitude of $\vec{F}$ is (Use $ g = 10\,m/s^2$)
- A metre scale made of steel reads accurately at $25^{\circ} C$ . Suppose in an experiment an accuracy of $0.06\, mm$ in $1\,m$ is required, the range of temperature in which the experiment can be performed with this metre scale is (coefficient of linear expansion of steel is $ 11 \times 10^{-6} /^{\circ} \, C$ )
- Consider a solenoid carrying current supplied by a DC source with a constant emf containing iron core inside it. When the core is pulled out of the solenoid, the change in current will
- A parallel beam of light of intensity \(I_0\) is incident on a coated glass plate. If \(25\%\) of the incident light is reflected from the upper surface and \(50\%\) of light is reflected from the lower surface of the glass plate, the ratio of maximum to minimum intensity in the interference region of the reflected light is
- A thermocol box has a total wall area (including the lid) of $1.0 m ^{2}$ and wall thickness of $3 cm$. It is filled with ice at $0^{\circ} C$. If the average temperature outside the box is $30^{\circ} C$ throughout the day, the amount of ice that melts in one day is [Use $K_{\text {thermocol }}=0.03 W / mK$ $.L_{\text {fusion (ice) }}=3.00 \times 10^{5} J / kg ]$
Top TS EAMCET laws of motion Questions
- A block of mass $10 \,kg$, initially at rest, makes a downward motion on $45^{\circ}$ inclined plane. Then the distance travelled by the block after $2 s$ is (Assume the coefficient of kinetic friction to be $0.3$ and $g=10\, ms ^{-2} )$
A player can throw a ball to a maximum horizontal distance of 80 m. If he throws the ball vertically with the same velocity, then the maximum height reached by the ball is:
A ball falls freely from a height h on a rigid horizontal plane. If the coefficient of resolution is e, then the total distance travelled by the ball before hitting the plane second time is:
A man weighing 75 kg is standing in a lift. The weight of the man standing on a weighing machine kept in the lift when the lift is moving downwards freely under gravity is:
- A 60 kg man standing on a bridge, jumps vertically down onto a 540 kg boat moving in the river below him with a speed of 10 m/s. The change in the speed of the boat is:
Top TS EAMCET Questions
- A bag contains $5$ red balls, $3$ black balls and $4$ white balls are drawn at random. The probability that they are not of same colour is
- If $cosec\, \theta - \cot \theta = 2017$, then quadrant in which $\theta $ lies is
- If $a$ is a unit vector, then $| a \times \hat{ i }|^{2}+| a \times \hat{ j }|^{2}+| a \times \hat{ k }|^{2}=$
- $A$ straight line makes an intercept on the $Y$-axis twice as long as that on $X$-axis and is at a unit distance from the origin. Then the line is represented by the equations
- Let $S$ and $S'$ be the foci of an ellipse and B be one end of its minor axis. If $SBS'$ is an isosceles right angled triangle then the eccentricity of the ellipse is
Concepts Used:
Laws of Motion
The laws of motion, which are the keystone of classical mechanics, are three statements that defined the relationships between the forces acting on a body and its motion. They were first disclosed by English physicist and mathematician Isaac Newton.
Newton’s First Law of Motion
Newton’s 1st law states that a body at rest or uniform motion will continue to be at rest or uniform motion until and unless a net external force acts on it.
Newton’s Second Law of Motion
Newton's 2nd law of motion deals with the relation between force and acceleration. According to the second law of motion, the acceleration of an object as built by a net force is directly proportional to the magnitude of the net force, in the same direction as the net force, and inversely proportional to the mass of the object.
Newton’s Third Law of Motion
Newton's 3rd law of motion states when a body applies a force on another body that there is an equal and opposite reaction for every action.