This question is incomplete, the complete question is;
The two 60 cm in diameter cylinders in Figure 13.15, closed at one end, open at the other, are joined to form a single cylinder, then the air inside is removed.
a) How much force does the atmosphere exert on the flat end of each cylinder?
b) Suppose one cylinder is bolted to a sturdy ceiling. How many 81 kg football players would need to hang from the lower cylinder to pull the two cylinders apart ?
Answer:
a) the atmosphere exert a force of 2.9 × 10⁴ N on the flat end of each cylinder
b) 36 football players each of 81 kg are needed to pull the two cylinders apart.
Step-by-step explanation:
Given that;
diameter of cylinder is 60 cm = 0.6 m
then radius r will be 0.6/2 = 0.3 m
a)
How much force does the atmosphere exert on the flat end of each cylinder;
we know that; F = PA
inside its the flats end that its in question; Area A = πr².
We Know that, Pressure P due to atmosphere is 1.013 × 10⁵ Pa
so, F = 1.013 × 10⁵ Pa × π( 0.3 )²
F = 1.013 × 10⁵ Pa × 0.09π
F = 28641.9 N ≈ 2.9 × 10⁴ N
Therefore, the atmosphere exert a force of 2.9 × 10⁴ N on the flat end of each cylinder.
b) number of players needed to pull the two cylinders apart.
given that; m = 81 kg and g is 9.8 m/s²
n = F / mg
we substitute
n = 28641.9 / (81 × 9.8)
n = 28641.9 / 793.8
n = 36.08 ≈ 36
Therefore, 36 football players each of 81 kg are needed to pull the two cylinders apart.