Physics CA

The expression M^a L^b T^c, when a = 1, b = 2 and c = -2 is the dimension of

• Force

• Energy

• Acceleration

• Power

     The most suitable instrument for measuring the diameter of a thin wire accurately is

• a metre rule

• a pair of vernier callipers

• a micrometer screw gauge

• a ruler

       A body accelerated uniformly from rest covers a distance of 8m in 2 seconds. The distance covered in the third second is

• 18m

• 12m

• 10m

• 4m

Centripetal acceleration of an object moving at constant speeds around a circular path is I. directly proportional to speed of the object II. directly proportional to the mass of the object. III. directly proportional to the square of the speed of the object IV inversely proportional to the radius of the circular path. Which of the  above statements are correct?

• I and II

• II, III and IV

• III and IV

• II and III.

  Two masses separated by a distance d attract each other with a gravitational force of 12N. If the separation between the masses is reduced to d/2, the gravitational force will

• increase to 48N

• increase 24N

• decrease to 6N

• decrease to 3N

An aircraft travelled from a point X to a point Y 100km away in the N45°E direction. It then travelled westwards to a point Z which is N45°W from X. The distance of the aircraft from X is

• 50km

• 100/√2 km

• 100km

• 100√2 km

An automobile travelling at a speed of 20m/s is brought uniformly to a halt in 10 seconds when a braking force of 5kN is applied. The mass of the automobile is

• 1000kg

• 1500kg

• 2000kg

• 2500kg

   The escape velocity of an object from the gravitational field of a planet I. increases with the mass of the object II. Increases with the mass of the planet III. Is smaller on the moon than on the earth. Which of the above statements is(are) correct?

• I only

• I and II only

• II and III only

• I, II and III

The unit cycles per second is the same as

• watt

• metres per second

• hertz

• radians per second

A stone of mass 50g tied to the end of a string of length 0.5m is whirled around in a horizontal circle of radius 0.5m at a constant speed of 20m/s. The tension in the string is

• 100N

• 40N

• 10N

• 4N