Question

2. Sally put her mug of coffee on the table. The mug has a mass of 1 kg. if the pressure

the applied by the mug of coffee is 1100 Pa, what is the surface area of the bottom of
the mug? What is the radius of the mug?

Answer 1

We have,

• The mass of sally's mug is 1 kg
• The pressure appliedby the mug is 1100 pascal.

We know that,

• Pressure = Force/Area

As, we already have the value of pressure, let's calculate that of force now;

• F = ma
• F = 1 × 9.8 { Acceleration due to gravity, let's round off it to 10}
• F = 10 N

Just put all the values in the formula now;

• P = F/A
• 1100 = 10 / A
• 1100/10 = A
• 110 m² = A

As, it is already mention that we need to find the radius of the mug, it is obviously a circular base.

We know that,

• Surface area = Circumference

So, let's solve it;

• Circumference = 2πr
• 110 = 2 × 22/7 × r
• 110 × 7/2 × 22 = r
• 5 × 7 = r
• 35 cm = r

Thus, the radius of the circle is 35 cm.