Assertion: Velocity and acceleration of a particle in circular motion at some instant are v = ( 3  ^ ) m / s and a = ( 4  ^ ) m / s 2 ; the radius of the circle is 4 9 m . Reason: The speed of the particle is decreasing at that instant.

The acceleration is entirely perpendicular to v , so a c = 4 m / s 2 and R = a c v 2 = 4 9 m (Assertion true). But a t = v v ⋅ a = 0 , so the speed is not changing at that instant and the Reason is false.

Start Free Mock LoginAlready registered? Login here

Physics - Circular Motion Question with Solution | TestHub

PhysicsCircular MotionKinematicsMedium2 minQB

PhysicsMediumassertion reason

Assertion: Velocity and acceleration of a particle in circular motion at some instant are $v =$ $(3 \overset{}{^}) m / s$ and $a = (4 \overset{}{^}) m / s^{2}$ ; the radius of the circle is $\frac{9}{4} m$ .

Reason: The speed of the particle is decreasing at that instant.

Options:

Answer:

Solution:

The acceleration is entirely perpendicular to $v$ , so $a_{c} = 4 m / s^{2}$
and $R = \frac{v ^{2}}{a _{c}}$
$= \frac{9}{4} m$ (Assertion true).
But $a_{t} = \frac{v \cdot a}{v} = 0$ , so the speed is not changing at that instant and the Reason is false.

Stream:JEESubject:PhysicsTopic:Circular MotionSubtopic:Kinematics

⏱ 2mℹ️ Source: QB

Doubts & Discussion

Loading discussions...