Question

Suppose that when you ride on your 7.50 kg bike the weight of you and the bike is supported equally by the two tires. If the gauge pressure in the tires is 65.5 lb/in^2 and the area of contact between each tire and the road is 7.03 cm^2. What is your weight?W=____ N

Answer 1

Answer: 567 N

Explanation:

If the weight of the person and the bike are supported equally by the two tires, this means that the force acting on each tire, is half of the total weight.

We know that the gauge pressure in one tire, by definition, is equal to the force on the tire, over the contact surface between each tire and the road, so we can write:

P= F/A = (mrider g + mbike g) / A = (Fgrider + 7.5 kg. 9.8 m/s2) / 703 mm2 (1)

As the pressure data is given in lb/in2, it is needed to convert to N/mm2, as follows:

65.5 lb/in2 = 0.455 N/mm2.

Replacing in (1), and solving for  Fgrider, we have:

Fgrider = 567 N