A car is moving at a speed of 72 km / hr. The diameter of its wheels is 0.5 m. If the wheels are stopped in 20 rotations applying brakes. Then angular retardation prodved by the brake is :

Question

A car is moving at a speed of 72 km / hr. The diameter of its wheels is 0.5 m. If the wheels are stopped in 20 rotations applying brakes. Then angular retardation prodved by the brake is : (A)  -45. 5 rad/s2 (B)  -33. 5 rad/s2 (C)  -29. 5 rad/s2 (D)  -25. 5 rad/s2

Tardigrade Admin · Accepted Answer

Here: Speed of car =72 km / hr =(72 × 5/18)=20 cm / s Diameter of each wheel =(0.5/2) m Number of rotation =20 The relation for angular speed is ω=(v/r)=(20/0.25)=80 rad / sec Angular displacement Q=2 π × 20=40 π rad The relation for angular retardation is given by ω2=ω02+2 a Q 0=(80)2+2 a(40 π) a=((80)2/80 π)=-25.5 rad / s 2

Q. A car is moving at a speed of $72 km / h r$ . The diameter of its wheels is $0.5 m$ . If the wheels are stopped in $20$ rotations applying brakes. Then angular retardation prodved by the brake is :

$- 45. 5 r a d / s^{2}$

$- 33. 5 r a d / s^{2}$

$- 29. 5 r a d / s^{2}$

$- 25. 5 r a d / s^{2}$

Q. A car is moving at a speed of 72km/hr. The diameter of its wheels is 0.5m. If the wheels are stopped in 20 rotations applying brakes. Then angular retardation prodved by the brake is :

−45.5rad/s2

−33.5rad/s2

−29.5rad/s2

−25.5rad/s2

Q. A car is moving at a speed of $72 km / h r$ . The diameter of its wheels is $0.5 m$ . If the wheels are stopped in $20$ rotations applying brakes. Then angular retardation prodved by the brake is :

$- 45. 5 r a d / s^{2}$

$- 33. 5 r a d / s^{2}$

$- 29. 5 r a d / s^{2}$

$- 25. 5 r a d / s^{2}$