Question

It takes _______sec for the tires of a racecar to make one revolution if the car is traveling at 270 km/hr, and the wheels have a radius of 0.350 m? (Record three significant digits, leading 0 are not significant, no units)

a) 0.46
b) 0.53
c) 0.72
d) 0.81

Answer 1

When converting the given speed from km/h to m/s and calculating the circumference of the tire, we find that the tire makes one revolution in 0.0294 seconds; however, this answer does not match any of the multiple-choice options given.

Step-by-step explanation:

The question is asking us to calculate the time it takes for the tires of a racecar to make one revolution if the car is traveling at 270 km/h with wheels that have a radius of 0.350 m. To solve this, we first convert the speed from km/h to m/s: 270 km/h = 270 × (1000 m / 1 km) × (1 h / 3600 s) = 75 m/s. Next, we find the circumference of the tire, which is the distance the tire covers in one revolution: Circumference = 2π×radius = 2π× 0.350 m.

Now we calculate the time for one revolution: Time (sec) = Circumference / Speed. Plugging in the values, Time (sec) = (2π× 0.350 m) / 75 m/s. After performing the calculation, we get Time (sec) = 0.0294 s, which we can convert to milliseconds to match the answer options: 0.0294 s = 29.4 ms. To get the answer in seconds, we round to three significant digits, leading zeros are not significant, and no units are indicated in the choices.

Therefore, the correct answer is 0.0294 seconds, which does not match any of the options given (a) 0.46, (b) 0.53, (c) 0.72, (d) 0.81, and thus it appears there is a discrepancy between the computed answer and the multiple-choice options provided.