Physics, Chemistry and Biology: Post your doubts here!

Emmris

Emmris

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princess of cricket said:
do we need a scientific calculator in biology paper
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U can use it but it's not needed in paper 1 n paper 2 cuz normally it's theoretical part .... it's very rare dat u get calculations ( even if u get,it will b simple calculations) .....

Scientific calculator is recommended in paper 6 as it is practical part where most of the time there r calculations....
 
studyingrobot457

studyingrobot457

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Emmris said:
U can use it but it's not needed in paper 1 n paper 2 cuz normally it's theoretical part .... it's very rare dat u get calculations ( even if u get,it will b simple calculations) .....

Scientific calculator is recommended in paper 6 as it is practical part where most of the time there r calculations....
Click to expand...


any news about may june papers (how they were ,when is going out to be released etc)
 
Emmris

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Can someone please help and explain me this physics question on pressure .....

-> A bicycle pump of length 45cm contains air with a pressure of 100kPa. In order to force air into the tyre, it is necessary to move the piston 15cm down the barrel. Calculate the pressure inside the tyre assuming the temperature is kept constant.
 
Adeen Atif

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Emmris said:
Idk :( explain how u got the ans plz :)
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Ok, So since the pressure and height is given for the bicycle pump before being pressed (which is 100KPa aka 100 000Pa and Height=45cm) So by using these values you can easily find the density of air by the formula: Pressure= Height*Density*gravitiation force (which is 10). So by reaaranigng the formula we can get Density= Pressure/Height*10 which in this case would be 100 000/10*45
Now after finding the density (222.22 we found above) we will proceed onto the part after the piston has been pushed.
Since the height was 45 before and the piston is pressed 15cm so the height down the barrel will be 45-15=30cm
Now use the pressure formula again and since you already found the density you can now easily find the answer
Pressure=Density*Height*10 So.. Pressure down the barrel (aka applied to the cycle tire)= 222.22*30*10=66666.7Pa (66.7 KPa)
 
Emmris

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Adeen Atif said:
Ok, So since the pressure and height is given for the bicycle pump before being pressed (which is 100KPa aka 100 000Pa and Height=45cm) So by using these values you can easily find the density of air by the formula: Pressure= Height*Density*gravitiation force (which is 10). So by reaaranigng the formula we can get Density= Pressure/Height*10 which in this case would be 100 000/10*45
Now after finding the density (222.22 we found above) we will proceed onto the part after the piston has been pushed.
Since the height was 45 before and the piston is pressed 15cm so the height down the barrel will be 45-15=30cm
Now use the pressure formula again and since you already found the density you can now easily find the answer
Pressure=Density*Height*10 So.. Pressure down the barrel (aka applied to the cycle tire)= 222.22*30*10=66666.7Pa (66.7 KPa)
Click to expand...
Thank u :*
 
Adeen Atif

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Adeen Atif said:
Ok, So since the pressure and height is given for the bicycle pump before being pressed (which is 100KPa aka 100 000Pa and Height=45cm) So by using these values you can easily find the density of air by the formula: Pressure= Height*Density*gravitiation force (which is 10). So by reaaranigng the formula we can get Density= Pressure/Height*10 which in this case would be 100 000/10*45
Now after finding the density (222.22 we found above) we will proceed onto the part after the piston has been pushed.
Since the height was 45 before and the piston is pressed 15cm so the height down the barrel will be 45-15=30cm
Now use the pressure formula again and since you already found the density you can now easily find the answer
Pressure=Density*Height*10 So.. Pressure down the barrel (aka applied to the cycle tire)= 222.22*30*10=66666.7Pa (66.7 KPa)
Click to expand...
Phew that was long:p
And since I did't know the exact answer I'm not sure about my answer it could be wrong too. But this was the only way to do so.
 
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