Suppose an automobile engine can produce 180 N*m of torque, and assume this car is suspended so that the wheels can turn freely. Each wheel acts like a 15.5 kg disk that has a 0.175 m radius. The tires act like 1.9-kg rings that have inside radii of 0.19 m and outside radii of 0.315 m. The tread of each tire acts like a 12-kg hoop of radius 0.335 m. The 14.5-kg axle acts like a solid cylinder that has a 1.95-cm radius. The 32.5-kg drive shaft acts like a solid cylinder that has a 2.9-cm radius.
(a) calculate the angular acceleration in radians per square second, produced by the motor if 95.0% of this torque is applied to the drive shaft, axle, and rear wheels of a car.

Explanation:

Moment of inertia of each wheel = 1/2 m R²

m is mass and R is radius of wheel

= .5 x 15.5 x .175²

= .2373 kg m²

moment of inertia of tyre

1/2 m ( r₁² + r₂² )

= 1/2 x 1.9 x ( .315² + .19²)

= 1/2 x 1.9 x ( .099+ .036)

= .12825 kg m²

moment of inertia of tread

= 1/2 m r²

= .5 x 12 x .335²

= .67335 kg m²

moment of inertia of axle

= 1/2 m r ²

= .5 x 14.5 x .0195²

= .00275

moment of inertia of drive shaft

= 1/2 x 32.5 x .029²

= .0137 kg m ²

Total moment of inertia of one tyre

=  1.05535 kg m²

total moment of inertia of two rear wheels

= 2.1107 kg m²

95 % of torque

= .95 x 180

= 171 Nm

angular acceleration

= torque / moment of inertia

= 171 / 2.1107

= 81.01 radian /s²

when insulating materials rub against each other, they may become electrically charged . electrons , which are negatively charged, may be 'rubbed off' one material and on to the other. the material that gains electrons becomes negatively charged. the material that loses electrons is left with a positive charge.