Question bank/JEE Main/Physics

JEE MainPhysicsModerateSimple Harmonic Motion

A 20 gm particle is subjected to two simple harmonic motions
x_1 = 2 sin 10 t,

x2=4sin(10t+π3)x_{2} = 4sin\left( 10t + \frac{\pi}{3} \right)where x_1& x_2 are in
metre& t is in sec.

Show answer and solution
At t = 0
Displacement
x=x1+x2=4sinπ2=23mx = x_{1} + x_{2} = 4sin\frac{\pi}{2} = 2\sqrt{3}m
Resulting Amplitude

A=22+42+2(2)(4)cosπ/3=4+16+8=28=27mA = \sqrt{2^{2} + 4^{2} + 2(2)(4)cos\pi/3} = \sqrt{4 + 16 + 8} = \sqrt{28} = 2\sqrt{7}m
Maximum speed
=Aω=207m/s= A\omega = 20\sqrt{7}m/s
Maximum acceleration
=Aω2=2007m/s2= A\omega^{2} = 200\sqrt{7}m/s^{2}

Source: Grass-G / P-23 Physcis Paper 31 Dec FST.docx

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