Circular Motion | MCQs

Explanation

Centripetal force is any force that keeps an object moving in a circular path, directed toward the center of the circle.

Tension in a string, gravitational force (like planets orbiting), and friction (like a car turning) can all provide centripetal force.

Explanation

Centripetal force acts perpendicular to the direction of motion, so it does no work.

Work = Force × Displacement × cos(θ); since θ = 90°, cos(90°) = 0, so Work = 0.

Explanation

Explanation

A body moving in a circular path with constant speed has variable acceleration. 

While the speed remains constant, the direction of the velocity vector is constantly changing as the body moves around the circle.

Since acceleration is the rate of change of velocity, and velocity is changing (even though speed is constant),

The body experiences a constant magnitude of acceleration

But the direction of that acceleration changes at every point on the circle.

This makes the acceleration variable. 

Explanation

The correct answer is:  All of the above

A complete revolution corresponds to an angular displacement of:

• 360°

• $2\pi$ radians

So, for 2 complete revolutions:

• Degrees: $2\times 360°=720°$

• Radians: $2 times 2pi = 4pi$ radians

• Approximate radians:

  $$4\pi \approx 4\times 3.14=12.56\text{ radians (rounded to 12.6)}$$

Explanation

Given:

• Radius of the circle$r=4$ meters

• Arc length (distance along the circumference), $s=14$ meters

We are to find the displacement, which is the straight-line distance between the starting and ending points of the arc.

Step 1: Find the angle subtended by the arc at the center (θ in radians):

$$theta = frac{s}{r} = frac{14}{4} = 3.5 , text{radians}$$

Step 2: Use the chord length formula to find displacement:

Displacement=2rsin(θ/2​)
=2×4×sin(3.5/2​)=8×sin(1.75)
sin(1.75radians)≈0.983
$$\text{Displacement}\approx 8\times 0.983\approx 7.864\text{meters}$$

Explanation

Explanation

In uniform circular motion, instantaneous velocity is tangent to the circular path.

Instantaneous acceleration (centripetal) is directed toward the center, making the two vectors perpendicular to each other.

Explanation

The acceleration of a particle moving in a uniform circular motion is directed towards the center of the circle and is given by:

a = v^2 / r

This is known as centripetal acceleration.

Explanation