if a car Tyre has a 20 inch radius, how many revolutions per second
would this car have to generate to arrive at 150 km/h speed.
argggh, what kind of a texbook would mix metric with non-metric units ??
anyway ...
20 inches = 20(2.54) cm
= 50.8 cm
one rotation would cover
2π(50.8) cm
or 319.1858. (I stored it on calculator)
150 km/h = 150(1000)100)/3600 cm/s
= 4166.666.. cm/s
number of revolutions
= 4166.6666../319.1856..
= 13.054
appr 13 rotations per second
check my arithmetic