Question

A wheel on a race car has 21-inch diameter. To qualify for an upcoming race, cars must be able to travel a minimum of 130 miles per hour. The wheel on this car can turn at the rate of 36 revolutions per second. Determine the linear speed of a point on the rim of this wheel (nearest inch per second) and determine if this car with this wheel would qualify for the upcoming race. 5 To convert inches per second to miles per hour, multiply by 5/88.

A) The linear speed is 756 inches per second, so this car would not quality
B) The linear speed is 4750 inches per second, so this car would quality
C) The linear speed is 2375 inches per second, so this car would quality
D) The linear speed is 378 inches per second, so this car would not qualify.

Answer 1

Above is correct

Explanation:

Answer 2

Answer: B) The linear speed is 4750 inches per second, so this car would qualify.

Step-by-step explanation: To determine linear speed using revolutions per second, i.e., angular speed (ω):

v = ω.r

where r is radius.

As ω is in revolutions per second, transform into rad/s:

ω = 36 revolutions/s

1 revolution = 2π rad

ω = 36.2π rad/s

ω = 72π rad/s

Radius is 21 inches, which can be written as

r = 21 inches/rad

Linear speed is

v =
`(72.\pi rad)/(s) .(21 in)/(rad)`

v ≈ 4750 inches per seconds

Converting to miles per hour:

v =
`4750.(5)/(88)`

v = 270mph

At linear speed of 4750 inches per second, a car with wheel of radius 21-inch can qualify.