Question

Pre-Medical : A particle starts from rest and rotating under constant angular acceleration of 2 rad/s2 in a circle of radius 2m, angle covered in fifth second will be:- (1) 9 rad (2) 25 rad (3) 10 rad (4) 15 rad​

Answer 1

Explanation:

Angle covered in 5sec -

$1 \div 2 \times \alpha \times {t}^{2}$ = 1/2×2×25 = 25 rad

Angle covered in 4sec -

$1 \div 2 \times \alpha \times {t}^{2}$ = 1/2×2×16 = 16 rad

Angle traveled in 5th sec = 25 - 16 = 9rad

hope this will help you

Answer 2

The given values in the question

Angular acceleration= 2 rad/s²

Radius =2 meter

initial angular speed= 0 rad/s

We have to find the angle covered by the object in the 5th second.

θ=ω +γ/2(2n -1)

θ₅ = ω₁ +γ/2(2n-1)

θ₅ = 0 +2/2 ( 2*5 -1)

θ₅= 10 -1

θ₅ = 9 radian

The angle covered in the fifth second will be 9 radians.

Hence, the option would be A.