Uniform Circular Motion - NEET Physics Questions
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Uniform Circular Motion

Question 1: easy

A wheel having diameter of 3 m starts from rest and accelerates uniformly to an angular velocity of 210 rpm in 5 seconds. Angular acceleration of the wheel is :

1. 1.4π rad/s²
2. 3.3π rad/s²
3. 2.2π rad/s²
4. 1.1π rad/s²
View Answer

ω = ω + α . t 

⇒(210 × 2π)/60 = 0 + α × 5 

⇒ α = 1.4 π rad/sec ²

Question 2: easy

The angular velocity of earth about its axis of rotation is :

1. 2π/(60×60×24) rad/sec
2. 2π/(60×60) rad/sec
3. 2π/60 rad/sec
4. 2π/(365×24×60×60) rad/sec
View Answer

Angular speed ω = 2π / T = 2π / (60×60×24) rad /sec 

Question 3: easy

Two bodies of masses 10 kg and 5 kg moving on concentric orbits of radii R and r such that their period of revolution are same. The ratio of their centripetal acceleration is :

1. R/r
2. r/R
3. R²/r²
4. r²/R²
View Answer

As time period of revolution is same for both the particles angular speed will be equal for both.

Centripetal Acceleration is given by ω²r.

so a 1 / a 2 = R/r

Question 4: easy

A stone of mass m is tied to a string of length l and rotated in a circle with a constant speed v. If the string is released, the stone flies :

1. radially outward
2. radially inward
3. tangentially
4. with an acceleration mv2/l
View Answer

In Circular motion velocity of the particle is always directed along tangent. So when string is released object moves tangentially.

Question 5: easy

A stone of mass 1 kg tied to one end of a string 1.0 m long is revolved in a horizontal circle at the rate of 10/π revolution per second. Calculate the tension of the string ?

1. 300 N
2. 400 N
3. 500 N
4. 600 N
View Answer

Tension force in the string will provide required centripetal force

T = mω²r= 1× (10/π ×2π)²×1= 400 N

Question 6: easy

A particle moves in a circle of radius 5 m with constant speed and time period 2π s. The acceleration of the particle is :

1. 15 m/s²
2. 25 m/s²
3. 36 m/s²
4. 5 m/s²
View Answer

As speed of the particle is constant only centripetal acceleration will act on the object.

Centripetal Acceleration = ω²R

a c = (2π/2π)× 5= 5 m/s²