Download App

2. motion in straight line — Physics STD 11 Science — Question

Rajasthan BoardEnglish MediumSTD 11 SciencePhysics2. motion in straight line1 Mark
MCQ
$Assertion$ : In a free fall, weight of a body becomes effectively zero.

$Reason$ : Acceleration due to gravity acting on a body having free fall is zero.

  • A
    If both Assertion and Reason are correct and the Reason is a correct explanation of the Assertion.
  • B
    If both Assertion and Reason are correct but Reason is not a correct explanation of the Assertion.
  • C
    If both the Assertion and Reason are incorrect.
  • ✓
    If the Assertion is correct but Reason is incorrect.
✓

Answer

Correct option: D.
If the Assertion is correct but Reason is incorrect.
d
In a free fall, effective weight of a body becomes zero. The reason behind it is the normal force acting on the object is equal to $mg$ which is same as the weight of the object. So, the object feels weightless. Actual weight during free fall is $mg$.

The acceleration due to gravity on the object falling down is $9.8\; m / s ^{2}$. It is non zero.

Need a full question paper?

Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.

Start Generating Free

Explore more

More "M.C.Q (1 Marks)" from 2. motion in straight line→2. motion in straight line — all question types→Physics STD 11 Science question papers→Rajasthan Board STD 11 Science question papers→Rajasthan Board question paper generator→

Similar questions

A block of mass $m$ starts at rest at height $h$ on a frictionless inclined plane. The block slides down the plane, travels across a rough horizontal surface with coefficient of kinetic friction $μ$ , and compresses a spring with force constant $k$ a distance $x$ before momentarily coming to rest. Then the spring extends and the block travels back across the rough surface, sliding up the plane. The block travels a total distance $d$ on rough horizontal surface. The correct expression for the maximum height $h’$ that the block reaches on its return is
→
The equation of the propagating wave is $y = 25\sin (20t + 5x),$ where $y$ is displacement. Which of the following statement is not true
→
A glass full of hot milk is poured on the table. It begins to cool gradually. Which of the following is correct?
  1. The rate of cooling is constant till milk attains the temperature of the surrounding.
  2. The temperature of milk falls off exponentially with time.
  3. While cooling, there is a flow of heat from milk to the surrounding as well as from surrounding to the milk but the net flow of heat is from milk to the surounding and that is why it cools.
  4. All three phenomenon, conduction, convection and radiation are responsible for the loss of heat from milk to the surroundings.
→
A cylinder of mass $M$ and radius $r$ is mounted on a frictionless axle over a well. A rope of negligible mass is wrapped around the cylinder and a bucket of mass $m$ is suspended from the rope. The linear acceleration of the bucket will be
→
A particle of mass $m$ is thrown upwards from the surface of the earth, with a velocity $u.$ The mass and the radius of the earth are, respectively, $M$ and $R.$  $G$ is gravitational constant and $g$ is acceleration due to gravity on the surface of the earth. The minimum value of $u$ so that the particle does not return back to earth, is
→
A ball is rolled off the edge of a horizontal table at a speed of $4\, m/second$. It hits the ground after $0.4\, second$. Which statement given below is true
→
An aeroplane moving horizontally at a speed of $200\;m/s$ and at a height of $8\;km$ is to drop a bomb on a target. At what horizontal distance from the target should the bomb be released..........$km$
→
A star is modeled as a uniform spherical distribution of matter keeping mass of star constant. How gravitational pressure on surface depends on volume of the star?
→
The upper portion of an inclined plane of inclination $\alpha $ is smooth and the lower portion is rough. A particle slides down from rest from the top and just comes to rest at the foot. If the ratio of the smooth length to rough length is $m : n$ , the coefficient of friction is
→
A pendulum is formed by pivoting a disc. What distance from center of mass, it should be pivoted for minimum time period while performing $SHM$ ?
→