The tyre pressure of a car was found to be 150cmHg in the morning at a temperature of 27°C. Hard driving in the afternoon raised the temperature of the tyres to 57°C. The tyre pressure had by the afternoon was?

De sage

1 year ago

p1= 150cmHg
T1=27°c+273=300k
p2=?
T2= 57°c+273=300k

using pressure law

P1/T1=P2/T2

150/300=P2/330
therefore

P2=150×330÷300

P2=165cmhg.

(remember P2 increase oo)
checking the options
P2-P1
165-150=15
15(increased) .

therefore A is correct

Abdullahi113

1 year ago

I think my school should review the answer because the answer is not provided in the options

leoflex

10 years ago

The question is wrongly composed:

there is supposed to be pressure

henrilism

10 years ago

The initial pressure wasn't given.

Johnson_Oweka

7 years ago

The initial pressure was not given

jadatis

5 years ago

Addition to my first error report.
150mmHG is measured overpressure over the ambiënt pressure of 76cmHg.
So right calc : 357/300 x ( 150+76) -76= 192.9 cm Hg, so 42.9 cmHg rising.
Assuming vollume of tyre dont rise by the higher pressure, wich is about right at an already pressurised tyre.

jadatis

5 years ago

Temp was raised by 57 degr C. So became 27+57 = 84 degr C.
In the answer 57 degr C is used.
So 273+27= 300 degr K.goes to 357 degr K. Gives 357/300 x 150cmHg = 178cm Hg.
So 28cm rising of pressure.
So no answer is right.