On a ladder resting on a rough ground and leaning against a smooth vertical wall, the force of friction acts

 

(A) zero at its upper end

 

(B) upwards at its upper end

 

(C) perpendicular to the wall at its upper end

 

(D) downwards at its upper end

One half of a vibration of a body, is called

(A) amplitude

(B) beat

(C) oscillation

(D) periodic time

The acceleration of a particle moving along the circumference of a circle with a uniform speed, is directed

(A) tangentially at that point

(B) away from the centre

(C) towards the centre

(D) radially

A satellite moves in its orbit around the earth due to

(A) centripetal force

(B) centrifugal force

(C) gravitational force

(D) none of these

A stone is whirled in a vertical circle, the tension in the string is maximum

(A) when the string is horizontal

(B) when the stone is at the lowest position

(C) when the stone is at the highest position

(D) at all the positions

In simple harmonic motion, acceleration of a particle is proportional to

(A) direction

(B) velocity

(C) displacement

(D) rate of change of velocity

The apparent weight of a man in a moving lift is less than his real weight when it is going down with

(A) retardation

(B) linear momentum

(C) uniform speed

(D) an acceleration

Energy may be defined as

(A) capacity of doing work

(B) rate of doing work

(C) power of doing work

(D) all the above

The unit of force in C.G.S. system of units is called

(A) kg

(B) dyne

(C) newton

(D) all the above

Ground water is usually free from

(A) dissolved impurities

(B) suspended impurities

(C) both suspended and dissolved impurities

(D) none of the above

The suitable method for disinfection of swimming pool water is

(A) chlorination

(B) by using potassium permanganate

(C) ultra violet rays treatment

(D) lime treatment