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Which one of the following statements is not true?

(A) Friction helps us to twist an object

(B) Friction is a force that opposes motion

(C) Objects have weight because of the frictional force between them and the Earth

4 The speed of a train increases at a constant rate a from zero to v, and then remains constant for an interval, and finally decreases to zero at a constant rate b. If L be the total distance travelled, then the total time taken is

(A)

(B)

(C)

A particle is moving in a straight line with initial velocity u and uniform acceleration f. If the sum of the distances travelled in t^th and (t + 1)^th seconds is 100 cm, then its velocity after t seconds in cm/s is

(A) 20

(B) 30

(C) 50

(A) To increase the enjoyment of travelling in a train

(B) To make the travel adventurous

(C) To cross the rivers and mountains

(D) To protect the train from accidents.

Which square must be shaded so that the figure has a line of symmetry ?

(A) 1

(B) 2

(C) 3

(D) 4

A solid cube is painted blue on all faces and then cut into 125 small cubes. How many cubes are there which are not painted on any of the faces?

(a) 8
(b) 16
(c) 27
(d) 36

A particle of mass 0.3 kg is subjected to a force F = kx with k = 15 N/m and x being its distance from the origin. What will be its initial acceleration if it is released from a point 20 cm away from the origin ?

(A) 5 m/s²

(B) 10 m/s²

(C) 3 m/s²

(A) They catch food

(B) They store water

(C) They protect the plant from being eaten by animals

(D) They make the plant attract bees.

(A)

(B)

(C)

(D)

A particle is acted upon by a constant force, the magnitude of which is always perpendicular to the velocity of particle. The motion of particle takes place in same plane. From the above statement it implies

(A) Particle is moving in a circular path

(B) Magnitude of its acceleration is constant

(C) Its velocity is uniform