Physics, Chemistry and Biology: Post your doubts here!

[Emmris]

do we need a scientific calculator in biology paper

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]

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....

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

 

[Emmris]

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

Nope idk ...

 

[studyingrobot457]

u have IGCSE next year (june 2018) right?

if so , good luck for us

 

[Emmris]

No I'm giving o level

 

[studyingrobot457]

No I'm giving o level

anyway good luck

 

[Emmris]

anyway good luck

Thnx n same 2 u

 

[Emmris]

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.

 

[Emmris]

https://drive.google.com/file/d/0B3wFBXa2u3AdcmlFc2xsakpUUTA/view?usp=drivesdk

 

[Emmris]

Adeen Atif, Ayesha Asif333, hellen, Hasnain the rocker help !!

 

[Adeen Atif]

Adeen Atif, Ayesha Asif333, hellen, Hasnain the rocker help !!

Is the answer 66.7 KPa?

 

[Emmris]

Is the answer 66.7 KPa?

Idk explain how u got the ans plz

 

[Adeen Atif]

Idk explain how u got the ans plz

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]

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)

Thank u :*

 

[Adeen Atif]

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)

Phew that was long
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.

 

[Emmris]

Nah it must b right

 

[Adeen Atif]

Thank u :*

No problem. Happy to help

 

[Adeen Atif]

Nah it must b right

Should be lol

 

[Emmris]

Should be lol

 

[Emmris]

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)

I didn't knew abt the formula pressure=density * height .....