The maximum speed and acceleration of a particle executing simple harmonic motion are 10 cm/s and 50 cm/s2. Find the position(s) of the particle when the speed is 8 cm/s.
Solution
It is given that:
Maximum speed of the particle, \[v_{Max}\]= `10 "cm"^(- 1)`
Maximum acceleration of the particle,
\[\Rightarrow \omega^2 = \frac{50}{A} . . . (2)\]
\[\text { From the equations (1) and (2), we get:} \]
\[\frac{100}{A^2} = \frac{50}{A}\]
\[ \Rightarrow A = 2 cm\]
\[ \therefore \omega = \sqrt{\frac{100}{A^2}} = 5 \sec^{- 1}\]
To determine the positions where the speed of the particle is 8 ms-1, we may use the following formula:
v2 = ω2 (A2 − y2)
where y is distance of particle from the mean position, and
v is velocity of the particle.
On substituting the given values in the above equation, we get:
64 = 25 (4 − y2)
\[\Rightarrow \frac{64}{25} = 4 - y^2\]
⇒ 4 − y2 = 2.56
⇒ y2 = 1.44
⇒ y = \[\sqrt{1 . 44}\]
⇒ y = ± 1.2 cm (from the mean position)