Q11 of 31 Page 358

Figures 14.25 correspond to two circular motions. The radius of the circle, the period of revolution, the initial position, and the sense of revolution (i.e. clockwise or anti-clockwise) are indicated on each figure.


Obtain the corresponding simple harmonic motions of the x-projection of the radius vector of the revolving particle P, in each case.

We know as a particle move in circular path the projection on x and y axis of displacement covered by particle represent a simple harmonic motion as the particle moves the angle subtended by it changes and if velocity is uniform its angular velocity or rate of change of angle subtended at centre with respect to original position become constant (a fixed value), projections can be represented as a function of sine and cosine in terms of angular velocity or time period and time


(a) Here particle started from a point on negative Y axis and started moving in a circular path in clockwise direction, now the time period of one complete rotation is given as T = 2s, so the particle will return to its original position in 2s, so after 1 second it will be on diametrically opposite point


Now let angle made by line joining particle to centre make an angle

More from this chapter

All 31 →
9

A spring having with a spring constant 1200 N m–1 is mounted on a horizontal table as shown in Fig. 14.24. A mass of 3 kg is attached to the free end of the spring. The mass is then pulled sideways to a distance of 2.0 cm and released.


Determine (i) the frequency of oscillations, (ii) maximum acceleration of the mass, and (iii) the maximum speed of the mass.

10

In Exercise 14.9, let us take the position of mass when the spring is unstreched as x = 0, and the direction from left to right as the positive direction of x-axis. Give x as a function of time t for the oscillating mass if at the moment we start the stopwatch (t = 0), the mass is

(a) at the mean position,


(b) at the maximum stretched position, and


(c) at the maximum compressed position.


In what way do these functions for SHM differ from each other, in frequency, in amplitude or the initial phase?

12

Plot the corresponding reference circle for each of the following simple harmonic motions. Indicate the initial (t =0) position of the particle, the radius of the circle, and the angular speed of the rotating particle. For simplicity, the sense of rotation may be fixed to be anticlockwise in every case: (x is in cm and t is in s).

x = –2 sin (3t + π/3)

12

Plot the corresponding reference circle for each of the following simple harmonic motions. Indicate the initial (t =0) position of the particle, the radius of the circle, and the angular speed of the rotating particle. For simplicity, the sense of rotation may be fixed to be anticlockwise in every case: (x is in cm and t is in s).

x = cos (π/6 – t)