**LEVEL – I **

1. A particle moves in x-y plane according to the equation the motion of the particle is

(A) on a straight line

(B) on an ellipse

(C) periodic

(D) simple harmonic

2. Which of the following quantities are always positive in a simple harmonic motion ?

(A) F^{−>} . a^{−>}

(B) v^{−>} . r^{−>}

(C) a^{−>} . r^{−>}

(D) F^{−>} . r^{−>}

3. The magnitude of average acceleration in half time period in a simple harmonic motion is

(A) 2 ω^{2}A /π

(B) ω^{2}A /2 π

(C) ω^{2}A /√2 π

(D) Zero

4. A small block oscillates back and forth on a smooth concave surface of radius R. The time period of small oscillation is

(A) T = 2π √(R/g)

(B) T = 2π √(2R/g)

(C) T = 2π √(R/2g)

(D) None of these

5. A particle of mass 10 gm lies in a potential field v = 50 x^{2} + 100. The value of frequency of oscillations in Hz is

(A) 5 Hz

(B) 5/π Hz

(C) 10π/3 Hz

(D) none of these.

6. When two mutually perpendicular simple harmonic motions of same frequency , amplitude and phase are superimposed

(A) the resulting motion is uniform circular motion.

(B) the resulting motion is a linear simple harmonic motion along a straight line inclined equally to the straight lines of motion of component ones.

(C) the resulting motion is an elliptical motion, symmetrical about the lines of motion of the components.

(D) the two S.H.M. will cancel each other.

7. The angular frequency of small oscillations of the system shown in the figure is

(A) √(K / 2m)

(B) √(2K / m)

(C) √(K / 4m)

(D) √(4K / m)

8. A particle executes SHM with a frequency f. The frequency with which it’s KE oscillates is

(A) f/2

(B) f

(C) 2f

(D) 4f

9. A simple pendulum has some time period T. What will be the percentage change in its time period if its amplitudes is decreased by 5 % ?

(A) 6 %

(B) 3 %

(C) 1.5 %

(D) 0 %

10. The work done by the string of a simple pendulum during one complete oscillation is equal to

(A) total energy of the pendulum

(B) KE of the pendulum

(C) PE of the pendulum

(D) Zero

__Answers:__

1. (A) 2. (A) 3. (A) 4. (A) 5. (B) 6. (B) 7. (C) 8. (C) 9. (D) 10. (D)