861. The rotational K.E of the hoop is equal to the
A. its translational K.E
B. half than its translational K.E
C. double than its translational K.E
D. four times than its translational K.E

862. A hoop and disc have same mass and radius. Their rotational K.E are related by an equation
A. K.E hoop = K.E disc
B. K.E hoop = 2K.E disc
C. K.E hoop = 1/2K.E disc

863. The critical speed of an artificial satellite is
A. 8 Kms-1
B. 8.1 Kms-1
C. 7.9 Kms-1
D. 8 ms-1

864. Geostationary satellite completes one rotation around the earth in
A. 3 hours
B. 6 hours
C. 12 hours
D. 24 hours

865. The radius of geostationary orbit from the centre of the earth is nearly
A. 42000km
B. 36000km
C. 24000 km
D. 18000 km

866. According to Einstein, the gravitational interaction is possible between
A. material objects only
B. material objects and electromagnetic radiation only
D. none of the above

867. One radian is equal to
A. 67.3°
B. 57.3°
C. 87.3°
D. 60°

868. The period of a circular motion is given by
A. T = πv
B. T = πw
C. T = 2πr
D. T = 2πr/v

869. The direction of the linear velocity of a body moving in a circle is
A. along the axis of rotation
B. along the tangent
C. directed towards the centre
D. directed away from the centre

870. When a body moves in a circle, the angle between its linear velocity and angular velocity is always
A. 180°
B. 0°
C. 90°
D. 45°