Exams › NEET › Physics

An aeroplane revolves in a circle above the surface of the Earth at a fixed height with speed 100 km/h. The change in velocity after completing half a revolution is:

1. 200 km/h
2. 150 km/h
3. 300 km/h
4. 400 km/h

Correct answer: 200 km/h

Solution

In uniform circular motion, the speed remains constant but the direction of velocity changes continuously. After half a revolution, the velocity vector becomes opposite to the initial one, so the change in velocity has magnitude $2v = 200$ km/h. Hence the answer is 200 km/h.

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 →