Exams › NEET › Physics

A stone tied to one end of a string 80 cm long is whirled in a horizontal circle with constant speed. If the stone makes 14 revolutions in 25 s, the magnitude of its acceleration is:

1. 850 cm/s²
2. 996 cm/s²
3. 720 cm/s²
4. 650 cm/s²

Correct answer: 996 cm/s²

Solution

For uniform circular motion, centripetal acceleration is $a=\omega^2 r$. Here $f=14/25$ s$^{-1}$, so $\omega=2\pi(14/25)$ rad/s. Substituting $r=80$ cm gives $a\approx 996$ cm/s².

Related NEET Physics questions

• A stone tied to a string of length 80 cm is whirled in a horizontal circle at constant speed, completing 14 revolutions in 25 s. What is the magnitude of the centripetal acceleration of the stone?
• A coin on a rotating turntable begins to slip when placed 4 cm from the center. If the turntable's angular speed is doubled, at what distance from the center will the coin just start to slip?
• The angular displacement of a rotating body is described by $\theta(t) = \omega_0 t + \frac{1}{2}\alpha t^2$, where $\omega_0 = 1\ \text{rad/s}$ and $\alpha = 1.5\ \text{rad/s}^2$. What is the angular velocity of the body at $t = 2\ \text{s}$?
• A coin rests on a gramophone record rotating at angular velocity \(\omega\). The coefficient of static friction is \(\mu\). The coin rotates without slipping if its distance \(r\) from the center satisfies:
• Two racing cars of masses \(m_1\) and \(m_2\) travel in circles of radii \(r_1\) and \(r_2\), respectively. Both complete one full revolution in the same time period \(t\). What is the ratio of the angular speed of the first car to the second car?
• A wheel starts from rest and undergoes uniform angular acceleration, reaching an angular velocity of 80 rad/s after 5 seconds. What is the total angular displacement of the wheel during this time?

⚔️ Practice NEET Physics free + battle 1v1 →