**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**

C. electromagnetic radiations

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°