# Lesson Worksheet: Relating Force, Pressure, and Area Physics • 9th Grade

In this worksheet, we will practice using the formula for pressure, p = F/A, to calculate pressures that are produced by forces acting on areas.

Q1:

What pressure is exerted by a 100 N force applied to an area of 2.5 m2?

Q2:

Which of the following formulas correctly shows the relationship between an applied force, the pressure that the force produces, and the area on which the force acts?

• A
• B
• C
• D
• E

Q3:

An empty water tank has a rectangular base with side lengths of 1.2 m and 2.3 m. The weight of the tank applies a pressure of 350 Pa to the surface it is resting on. What is the weight of the tank?

Q4:

The bases of a man’s feet have a total area in contact with the ground of 0.025 m2. The man’s weight is 800 N. How much is the pressure applied by his feet to the ground in kilopascals?

Q5:

A pressure of 20 Pa is applied by an 8,000 N force to a square area. What is the length of a side of the square?

Q6:

A pressure of 75 Pa is applied by a 3,000 N force. What area is the force applied to?

Q7:

A pressure of 400 Pa is applied to an area of 2.5 m2. What force applies this pressure?

Q8:

A sofa with a mass of 125 kg has a base with an area of 2.5 m2. What pressure does the sofa apply to the ground beneath it?

Q9:

A dancer with a mass of 50 kg is standing on the tips of the toes of one of her feet. She exerts a pressure of 490 kPa on the tips. What is the area, in square centimeters, of the part of the foot on which she stands?

Q10:

A press is used to crack rocks, applying a pressure of 750 kPa to a rock with a mass of 6.2 kg, as shown in the diagram. The rock being crushed has a very uneven surface. The surface area in contact with the plates of the press is 20 cm2. What is the average force applied to the rock by the press?

How many times heavier would the rock being crushed need to be for it to apply the same weight to the ground as the average force applied by the press? Round your answer to one decimal place.