### Summation(superposition) of angular momentum

Posted:

**Sun Jan 21, 2007 10:47 am**From the book "3000 solved problems in Physics", page 238, queston 12.48:-

"Each of the wheels on a certain four-wheel vehicle has a mass of 30kg and a radius of gyration of 30 cm. When the car is going forward and the wheels are turning at 5.0 rev/s,

a) what is the rotational kinetic energy stored in the 4 wheels?

b) what is the angular momentum of the vehicle about an axis parallel to the wheel axis and through the center of mass?

c) Is the angular momentum vector directed towards the driver's right or left?"

Answer for the book:-

a) K = 5300J (ok)

b) L = 4 I w = 340kg.m^2/s (I disagree)

c) driver's left.(ok)

I disagreed with the answer (b) of the angular momentum as the car itself is not rotating, so how to get its angular momentum?? Only the wheels are rotating, so only the wheels have angular momentum.

Am I right to say that the angular momnetum of the car, L = 0?

"Each of the wheels on a certain four-wheel vehicle has a mass of 30kg and a radius of gyration of 30 cm. When the car is going forward and the wheels are turning at 5.0 rev/s,

a) what is the rotational kinetic energy stored in the 4 wheels?

b) what is the angular momentum of the vehicle about an axis parallel to the wheel axis and through the center of mass?

c) Is the angular momentum vector directed towards the driver's right or left?"

Answer for the book:-

a) K = 5300J (ok)

b) L = 4 I w = 340kg.m^2/s (I disagree)

c) driver's left.(ok)

I disagreed with the answer (b) of the angular momentum as the car itself is not rotating, so how to get its angular momentum?? Only the wheels are rotating, so only the wheels have angular momentum.

Am I right to say that the angular momnetum of the car, L = 0?