Laws Of Motion CBSE Questions & Answers

Laws Of Motion

This is Physics Class 11 Laws of Motion CBSE Questions & Answers. There are 15 questions in this test with each question having around four answer choices.

Questions & Answers

1
A man of mass 70 kg stands on a weighing scale in a lift which is moving upwards with a uniform speed of 10 m \({{\rm{s}}^{ - {\rm{1}}}}\), what would be the reading on the scale?
  • A
    35 kg
  • B
    105 kg
  • C
    70 kg
    Correct
  • D
    75 kg
2
A man of mass 70 kg stands on a weighing scale in a lift which is moving downwards with a uniform acceleration of 5 m \({{\rm{s}}^{ - {\rm{2}}}}\) what would be the reading on the scale?
  • A
    45 kg
  • B
    53 kg
  • C
    38 kg
  • D
    35 kg
    Correct
3
A man of mass 70 kg stands on a weighing scale in a lift which is moving upwards with a uniform acceleration of 10 m \({{\rm{s}}^{ - {\rm{2}}}}\) what would be the reading on the scale?
  • A
    150 kg
  • B
    130 kg
  • C
    140 kg
    Correct
  • D
    120 kg
4
A man of mass 70 kg stands on a weighing scale in a lift which is moving upwards with a uniform acceleration of 5 m \({{\rm{s}}^{ - {\rm{2}}}}\) what would be the reading on the scale?
  • A
    125 kg
  • B
    115 kg
  • C
    105 kg
    Correct
  • D
    95 kg Hz
5
A man of mass 70 kg stands on a weighing scale in a lift which is moving upwards with a uniform speed of 10 m \({{\rm{s}}^{ - {\rm{1}}}}\). What would be the reading if the lift mechanism failed and it hurtled down freely under gravity?
  • A
    70 kg
  • B
    0 kg
    Correct
  • C
    35 kg
  • D
    105 kg
6
Figure shows the position-time graph of a particle of mass 4 kg. What is the force on the particle for \({\text{t }} < {\text{ }}0,{\text{ t }} > {\text{ 4 s}},{\text{ }}0{\text{ }} < {\text{ t }} < {\text{ 4 s}}\)?
Question 6 figure 1
  • A
    0, 2, 0
  • B
    0, 1, 2
  • C
    0, 0, 0
    Correct
  • D
    0, 2, 1
7
Figure shows the position-time graph of a particle of mass 4 kg. What is the impulse at t = 0 and t = 4 s ? (Consider one-dimensional motion only)
Question 7 figure 1
  • A
    5 kg m \({{\rm{s}}^{ - {\rm{1}}}}\) at t=0 and -3 kg m \({{\rm{s}}^{ - {\rm{1}}}}\) at t = 4 s
  • B
    2 kg m \({{\rm{s}}^{ - {\rm{1}}}}\) at t=0 and -2 kg m \({{\rm{s}}^{ - {\rm{1}}}}\) at t = 4 s
  • C
    3 kg m \({{\rm{s}}^{ - {\rm{1}}}}\) at t=0 and -3 kg m \({{\rm{s}}^{ - {\rm{1}}}}\) at t = 4 s
    Correct
  • D
    4 kg m \({{\rm{s}}^{ - {\rm{1}}}}\) at t=0 and -4 kg m \({{\rm{s}}^{ - {\rm{1}}}}\) at t = 4 s
8
Two bodies of masses 10 kg and 20 kg respectively kept on a smooth, horizontal surface are tied to the ends of a light string. a horizontal force F = 600 N is applied to the 20 kg mass so as to pull it. What is the tension in the string?
  • A
    250 N
  • B
    300 N
  • C
    150 N
  • D
    200 N
    Correct
9
Two bodies of masses 10 kg and 20 kg respectively kept on a smooth, horizontal surface are tied to the ends of a light string. a horizontal force F = 600 N is applied to the 10 kg mass so as to pull it. What is the tension in the string?
  • A
    370 N
  • B
    300 N
  • C
    450 N
  • D
    400 N
    Correct
10
A nucleus is at rest in the laboratory frame of reference. If it disintegrates into two smaller nuclei
  • A
    the products must move at an angle in opposite directions.
  • B
    the products must move at an angle in same direction.
  • C
    the products must move in opposite directions.
    Correct
  • D
    the products must move in same direction.
11
Two billiard balls each of mass 0.05 kg moving in opposite directions with speed 6 m \({{\rm{s}}^{ - {\rm{1}}}}\) collide and rebound with the same speed. What is the impulse imparted to each ball due to the other?
  • A
    0.6 kg m \({{\rm{s}}^{ - {\rm{1}}}}\)
    Correct
  • B
    0.5 kg m \({{\rm{s}}^{ - {\rm{1}}}}\)
  • C
    0.4 kg m \({{\rm{s}}^{ - {\rm{1}}}}\)
  • D
    0.3 kg m \({{\rm{s}}^{ - {\rm{1}}}}\)
12
A shell of mass 0.020 kg is fired by a gun of mass 100 kg. If the muzzle speed of the shell is 80 m \({{\rm{s}}^{ - {\rm{1}}}}\), what is the recoil speed of the gun?
  • A
    1.9 cm/s
  • B
    1.7 cm/s
  • C
    1.8 cm/s
  • D
    1.6 cm/s
    Correct
13
A batsman deflects a ball by an angle of 45\(^\circ \) without changing its initial speed which is equal to 54 km/h. What is the impulse imparted to the ball? (Mass of the ball is 0.15 kg.)
  • A
    4.2 kg m \({{\rm{s}}^{ - {\rm{1}}}}\)
    Correct
  • B
    4.8 kg m \({{\rm{s}}^{ - {\rm{1}}}}\)
  • C
    4.6 kg m \({{\rm{s}}^{ - {\rm{1}}}}\)
  • D
    4.4 kg m \({{\rm{s}}^{ - {\rm{1}}}}\)
14
A stone of mass 0.25 kg tied to the end of a string is whirled round in a circle of radius 1.5 m with a speed of 40 rev./min in a horizontal plane. What is the tension in the string?
  • A
    6.6 N
    Correct
  • B
    6.1 N
  • C
    6.3 N
  • D
    6.9 N
15
A stone of mass 0.25 kg tied to the end of a string is whirled round in a circle of radius 1.5 m with a speed of 40 rev./min in a horizontal plane. What is the maximum speed with which the stone can be whirled around if the string can withstand a maximum tension of 200 N?
  • A
    35 m \({{\rm{s}}^{ - {\rm{1}}}}\)
    Correct
  • B
    38 m \({{\rm{s}}^{ - {\rm{1}}}}\)
  • C
    33 m \({{\rm{s}}^{ - {\rm{1}}}}\)
  • D
    37 m \({{\rm{s}}^{ - {\rm{1}}}}\) Hz