K223 Force and Pressure Quiz

What is the SI unit of force?

• Joule

• Newton

• Pascal

• Watt

Answer explanation

The SI unit of force is the Newton, named after Sir Isaac Newton. It is defined as the force required to accelerate a one-kilogram mass by one meter per second squared.

Which of the following is a non-contact force?

• Friction

• Air resistance

• Magnetic force

• Tension

Answer explanation

Magnetic force is a non-contact force that acts at a distance, unlike friction, air resistance, and tension, which require direct contact between objects.

What is the definition of mass?

• The gravitational force acting on a body that has mass

• The amount of matter in a body

• The amount of space taken up by a body

• The force per unit area acting on a body

Answer explanation

Mass is defined as the amount of matter in a body, distinguishing it from other concepts like weight, which is the gravitational force acting on that mass.

What is the relationship between weight and gravitational field strength?

• Weight = mass × gravitational field strength

• Weight = mass ÷ gravitational field strength

• Weight = gravitational field strength ÷ mass

• Weight = mass + gravitational field strength

Answer explanation

Weight is defined as the force exerted by gravity on an object, calculated using the formula: Weight = mass × gravitational field strength. This shows that weight increases with greater mass or stronger gravitational fields.

What is gravitational field strength (g) defined as?

• The gravitational force acting on a body that has mass

• The gravitational force per unit mass placed at a point

• The amount of matter in a body

• The force per unit area acting on a body

Answer explanation

Gravitational field strength (g) is defined as the gravitational force per unit mass placed at a point. This means it quantifies how much force is exerted by gravity on a unit mass at a specific location.

What is the property of an object that resists a change to its initial state of rest or uniform linear motion?

• Density

• Inertia

• Mass

• Weight

Answer explanation

Inertia is the property of an object that resists changes to its state of rest or uniform motion. It is directly related to mass, but specifically refers to the resistance to change, making 'Inertia' the correct answer.

How is density defined in terms of mass and volume?

• Density is the volume per unit mass.

• Density is the mass per unit volume.

• Density is the weight per unit volume.

• Density is the mass per unit weight.

Answer explanation

Density is defined as the mass of an object divided by its volume. Therefore, the correct choice is 'Density is the mass per unit volume,' which accurately describes this relationship.

What happens to the density of a substance when it is heated?

• Density increases because mass increases.

• Density decreases because volume increases.

• Density remains constant because mass and volume remain constant.

• Density increases because volume decreases.

Answer explanation

When a substance is heated, its volume typically increases due to thermal expansion. Since density is mass divided by volume, an increase in volume leads to a decrease in density, making the correct answer: Density decreases because volume increases.

What is the SI unit of density?

• Kilogram per cubic meter (kg/m³)

• Gram per cubic centimeter (g/cm³)

• Kilogram per liter (kg/L)

• Gram per liter (g/L)

Answer explanation

The SI unit of density is kilogram per cubic meter (kg/m³). This unit is used in scientific contexts to express mass per unit volume, making it the standard measurement for density in the International System of Units.

What is the SI unit of pressure?

• Newton

• Pascal

• Joule

• Watt

Answer explanation

The SI unit of pressure is the Pascal (Pa), defined as one newton per square meter. It measures force applied over an area, making it the correct choice among the options provided.