9) Suppose that when you ride on your 7.85-kg bike the weight of you and the bike is supported equally by the two tires. If the gauge pressure in the tires is 70.2 lb/in2 and the area of contact between each tire and the road is 7.03 cm2, what is your weight?

Respuesta :

Answer:

60.99 kg

Explanation:

The pressure is equal to the force divided by the area. In this case, the force is the weight of you and the bike, so we can write the following equation

[tex]P=\frac{F}{A}[/tex]

Where F is the weight, A is the area, and P is the pressure

So, solving for F, we get:

[tex]F=PA[/tex]

Now, we need to convert 70.2 lb/in² to kg/cm², so

[tex]70.2\frac{lb}{in^2}\times\frac{0.45\text{ kg}}{1\text{ lb}}\times\frac{1in^2}{6.4516cm^2}=4.89\operatorname{kg}/cm^2[/tex]

Now, the weight of you and the bike in one tire is equal to

F = (4.89 kg/cm²)(7.03 cm²) = 34.42 kg

Since this weight is supported by the two tires, the total weight of you and the bike is:

2 x 34.42 kg = 68.84 kg

Now, we can subtract the weight of the bike

68.84 kg - 7.85 kg = 60.99 kg

Therefore, your weight is 60.99 kg