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IIT-JEE-Physics–2005

1. A particle moves in a circular path with decreasing speed. Choose the correct statement :

(a) Angular momentum remains constant
(b) Acceleration (a) is towards the centre
(c) Particle moves in a spiral path with decreasing radius
(d) The direction of angular momentum remains constant

2. A block of mass m is at rest under the action of force F against a wall as shown in figure. Which of the following statement is incorrect?
(a) f = mg [where f is the frictional force]
(b) F = N [where N is the normal force]
(c) F will not produce torque
(d) N will not produce torque

3. A simple pendulum has time period T1. The point of suspension is now moved upward according to the relation y = Kt2, (K = 1 m/s2) where y is the vertical displacement. The time period now becomes T2. The ratio of (T12)/(T22 ) is (g = 10 m/s2).
(a) 6/5
(b) 5/6
(c) 1
(d) 4/5

4. From a circular disc of radius R and mass 9M, a small disc of radius R/3 is removed from the disc. The moment of inertia of the remaining disc about an axis perpendicular to the plane of the disc and passing through O is:

(a) 4MR2
(b) 40/9 MR2
(c) 10 MR2
(d) 37/9 MR2

5. Which of the following sets have different dimensions?
(a) Pressure, Young’s modulus, Stress
(b) Emf, Potential difference, Electric potential
(c) Heat, Work done, Energy
(d) Dipole moment, Electric flux, Electric field

6. The given graph shows the variation of velocity with displacement. Which one of the graph given below correctly represents the variation of acceleration displacement?