The "lead" in pencils is a graphite composition with a young's modulus of about 1x10^9 n/m^2 calculate the change in length of the lead in an automatic pencil if you tap it straight into the pencil with a force of 4.0 n. the lead is 0.50 mm in diameter and 60 mm long. (b) is the answer reasonable? that is, does it seem to be consistent with what you have observed when using pencils?

Part a)

Part b)

Yes it is reasonable but since this is very small so it is not observable to us while we are using the pencils

Explanation:

As we know that Young's modulus of a given material is

now we have

here we know

diameter = 0.50 mm

so we have

now we have

now we have

Part b)

Yes it is reasonable but since this is very small so it is not observable to us while we are using the pencils

energy stored in the capacitor= 9.72 x 10⁻⁴ j

explanation:

the energy stored in the capacitor is given by

e= 1/2 c v²

e= energy stored

c= capacitance= 1.5 µc= 1.5 x 10⁻⁶f

v= potential difference=36 v

so energy stored= e= 1/2 (1.5 x 10⁻⁶) (36)²

energy stored= 9.72 x 10⁻⁴j