Advertisements
Advertisements
Question
A particle is subjected to two simple harmonic motions of same time period in the same direction. The amplitude of the first motion is 3.0 cm and that of the second is 4.0 cm. Find the resultant amplitude if the phase difference between the motions is (a) 0°, (b) 60°, (c) 90°.
Advertisements
Solution
It is given that a particle is subjected to two S.H.M.s of same time period in the same direction.
Amplitude of first motion, A1 = 3 cm
Amplitude of second motion, A2 = 4 cm
Let ϕ be the phase difference.
The resultant amplitude \[\left( R \right)\] is given by,
\[R = \sqrt{A_1^2 + A_2^2 + 2 A_1 A_2 cos \phi}\]
(a) When ϕ = 0°
\[R = \sqrt{\left( 3^2 + 4^2 + \left( 2 \right)\left( 3 \right)\left( 4 \right) \cos 0^\circ\right)}\]
\[ = 7 \text { cm }\]
(b) When ϕ = 60°
\[R = \sqrt{3^2 + 4^2 + \left( 2 \right)\left( 3 \right)\left( 4 \right) \cos 60^\circ}\]
\[ = \sqrt{37} = 6 . 1 \text { cm }\]
(c) When ϕ = 90°
\[R = \sqrt{\left( 3^2 + 4^2 + \left( 2 \right)\left( 3 \right)\left( 4 \right)\cos 90^\circ\right)}\]
\[ = \sqrt{25} = 5 \text { cm }\]
APPEARS IN
RELATED QUESTIONS
State the differential equation of linear simple harmonic motion.
A small creature moves with constant speed in a vertical circle on a bright day. Does its shadow formed by the sun on a horizontal plane move in a sample harmonic motion?
A student says that he had applied a force \[F = - k\sqrt{x}\] on a particle and the particle moved in simple harmonic motion. He refuses to tell whether k is a constant or not. Assume that he was worked only with positive x and no other force acted on the particle.
A particle moves on the X-axis according to the equation x = A + B sin ωt. The motion is simple harmonic with amplitude
A wall clock uses a vertical spring-mass system to measure the time. Each time the mass reaches an extreme position, the clock advances by a second. The clock gives correct time at the equator. If the clock is taken to the poles it will
A pendulum clock keeping correct time is taken to high altitudes,
The motion of a torsional pendulum is
(a) periodic
(b) oscillatory
(c) simple harmonic
(d) angular simple harmonic
In a simple harmonic motion
Which of the following will change the time period as they are taken to moon?
(a) A simple pendulum
(b) A physical pendulum
(c) A torsional pendulum
(d) A spring-mass system
A particle executes simple harmonic motion with an amplitude of 10 cm and time period 6 s. At t = 0 it is at position x = 5 cm going towards positive x-direction. Write the equation for the displacement x at time t. Find the magnitude of the acceleration of the particle at t = 4 s.
All the surfaces shown in figure are frictionless. The mass of the care is M, that of the block is m and the spring has spring constant k. Initially the car and the block are at rest and the spring is stretched through a length x0 when the system is released. (a) Find the amplitudes of the simple harmonic motion of the block and of the care as seen from the road. (b) Find the time period(s) of the two simple harmonic motions.

The pendulum of a certain clock has time period 2.04 s. How fast or slow does the clock run during 24 hours?
A simple pendulum is suspended from the roof of a school bus which moves in a horizontal direction with an acceleration a, then the time period is
Write short notes on two springs connected in parallel.
What is meant by simple harmonic oscillation? Give examples and explain why every simple harmonic motion is a periodic motion whereas the converse need not be true.
A simple harmonic motion is given by, x = 2.4 sin ( 4πt). If distances are expressed in cm and time in seconds, the amplitude and frequency of S.H.M. are respectively,
A body oscillates with SHM according to the equation x = 5 cos `(2π"t" + π/4)`. Its instantaneous displacement at t = 1 sec is:
The displacement of a particle varies with time according to the relation y = a sin ωt + b cos ωt.
A container consist of hemispherical shell of radius 'r ' and cylindrical shell of height 'h' radius of same material and thickness. The maximum value h/r so that container remain stable equilibrium in the position shown (neglect friction) is ______.

A weightless rigid rod with a small iron bob at the end is hinged at point A to the wall so that it can rotate in all directions. The rod is kept in the horizontal position by a vertical inextensible string of length 20 cm, fixed at its midpoint. The bob is displaced slightly, perpendicular to the plane of the rod and string. The period of small oscillations of the system in the form `(pix)/10` is ______ sec. and the value of x is ______.
(g = 10 m/s2)
