Laws of Motion

Laws of Motion

Easy Questions
Moderate Questions
Difficult Questions

Mechanics

Physical World, Units and Measurements
Motion in a Straight Line
Motion in a Plane
Laws of Motion
Work, Energy and Power
Gravitation
Mechanical Properties of Solids
Mechanical Properties of Fluids
System of Particles and Rotational Motion
  1. A 500 kg car takes a round turn of radius 50 m with a velocity of 36 km/h. The centripetal force is








  1. View Hint View Answer Discuss in Forum

    Centripetal force =
    mv²
    		 =
    500 × (10)²
    r50

    = 1000 N [∵ 36 km/hr = 10 m/s]

    Correct Option: C

    Centripetal force =
    mv²
    		 =
    500 × (10)²
    r50

    = 1000 N [∵ 36 km/hr = 10 m/s]

  1. A body of mass 0.4 kg is whirled in a vertical circle making 2 rev/sec. If the radius of the circle is 1.2 m, then tension in the string when the body is at the top of the circle, is








  1. View Hint View Answer Discuss in Forum

    Given : Mass (m) = 0.4 kg
    Its frequency (n) = 2 rev/sec
    Radius (r) = 1.2 m. We know that linear velocity of the body (v) = ωr = (2πn)r
    = 2 × 3.14 × 1.2 × 2 = 15.08 m/s.
    Therefore, tension in the string when the body is at the top of the circle (T)

    =
    mv²
    		 - mg =
    0.4 × (15.08)²
    		 - (0.4 × 9.8)
    r2

    = 45.78 - 3.92 = 41.56 N

    Correct Option: A

    Given : Mass (m) = 0.4 kg
    Its frequency (n) = 2 rev/sec
    Radius (r) = 1.2 m. We know that linear velocity of the body (v) = ωr = (2πn)r
    = 2 × 3.14 × 1.2 × 2 = 15.08 m/s.
    Therefore, tension in the string when the body is at the top of the circle (T)

    =
    mv²
    		 - mg =
    0.4 × (15.08)²
    		 - (0.4 × 9.8)
    r2

    = 45.78 - 3.92 = 41.56 N

  1. What will be the maximum speed of a car on a road turn of radius 30 m if the coefficient of friction between the tyres and the road is 0.4 (Take g = 9.8 m/s²)








  1. View Hint View Answer Discuss in Forum

    r = 30 m and µ = 0.4.
    vmax = √μrg = √0.4 × 30 × 9.8 = 10.84 m/s

    Correct Option: A

    r = 30 m and µ = 0.4.
    vmax = √μrg = √0.4 × 30 × 9.8 = 10.84 m/s

  1. A particle of mass M is moving in a horizontal circle of radius R with uniform speed V. When it moves from one point to a diametrically opposite point, its








  1. View Hint View Answer Discuss in Forum

    On the diametrically opposite points, the velocities have same magnitude but opposite directions. Therefore, change in momentum is MV – (– MV) = 2MV

    Correct Option: C

    On the diametrically opposite points, the velocities have same magnitude but opposite directions. Therefore, change in momentum is MV – (– MV) = 2MV

  1. When milk is churned, cream gets separated due to








  1. View Hint View Answer Discuss in Forum

    Cream gets separated from a churned milk due to centrifugal force.

    Correct Option: B

    Cream gets separated from a churned milk due to centrifugal force.