Physics: Mass, Weight, and Gravitational Fields

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Questions and Answers

What causes air resistance on an object in motion?

The gravitational attraction of nearby objects

The temperature of the air surrounding the object

The speed at which the object is traveling through water

Friction between the object's motion and air particles (correct)

What happens when the force of air resistance equals the weight of a falling object?

The object continues to fall at a steady (terminal) speed (correct)

The object experiences no force acting on it

The object accelerates downward indefinitely

The object rises back to its original height

Which statement accurately describes the weight force of an object?

It is influenced by the object's shape and size

It is the product of the object's mass and the gravitational field strength (correct)

It is unrelated to the gravitational pull of the Earth

It decreases as the object ascends in the atmosphere

What is the result when an object falls through a uniform gravitational field?

The object accelerates until a constant speed is reached Signup and view all the answers

What role does collision with air particles play in the motion of an object?

It generates a frictional force that slows the object down Signup and view all the answers

What happens to the skydiver when air resistance equals the weight force?

The skydiver experiences terminal velocity. Signup and view all the answers

What causes the skydiver's acceleration to slow when the parachute is opened?

The increased surface area of the parachute. Signup and view all the answers

Initially, why do skydivers accelerate downwards?

The upward force of air resistance is small. Signup and view all the answers

What occurs to a skydiver after reaching a new slower terminal velocity with the parachute open?

The skydiver maintains a steady speed. Signup and view all the answers

What effect does an increase in speed have on the force of friction acting on a falling object?

It increases the force of friction. Signup and view all the answers

What is the SI unit for mass?

Kilogram Signup and view all the answers

How is weight defined?

Gravitational force on an object with mass Signup and view all the answers

What does gravitational field strength represent?

Force per unit mass in a gravitational field Signup and view all the answers

What is the approximate value of acceleration due to gravity near the Earth's surface?

9.8 m/s² Signup and view all the answers

Which statement is true regarding mass and weight?

Mass is always the same while weight can change with gravity. Signup and view all the answers

What is terminal velocity?

The speed when an object stops accelerating due to drag Signup and view all the answers

What effect does mass have on an object moving through a liquid?

Reduces acceleration due to increased drag Signup and view all the answers

What causes friction (drag) on an object moving through a gas?

Displacement of surrounding air molecules Signup and view all the answers

What is the approximate gravitational field strength near the Earth's surface?

9.8 m/s² Signup and view all the answers

What causes an object to heat up as it moves through air?

Frictional forces against the object Signup and view all the answers

In a vacuum, what determines the acceleration of freefall for all objects?

The strength of gravitational field Signup and view all the answers

What happens to the force of air resistance as the speed of a falling object increases?

It increases Signup and view all the answers

Which of the following statements about terminal velocity is accurate?

Both A and B are correct. Signup and view all the answers

What is drag in the context of motion through fluids?

A type of friction that opposes motion Signup and view all the answers

Which of the following best describes the motion of a skydiver shortly after jumping from a plane?

Air resistance starts small but increases with speed. Signup and view all the answers

How does the gravitational field strength on the Moon compare to that on Earth?

It is about 1.63 N/kg, making weight much less on the Moon. Signup and view all the answers

Study Notes

Mass and Weight

Mass is a scalar quantity measuring the amount of matter in an object.
Mass is measured in kilograms (kg).
Mass resists changes in motion.
Weight is a vector quantity measuring the gravitational force on an object.
Weight is measured in Newtons (N).
The weight of an object depends on its mass and the strength of the gravitational field.

Gravitational Field Strength

Gravitational field strength (g) is the force per unit mass acting on an object in a gravitational field, measured in N/kg.
On Earth, the gravitational field strength is approximately 9.81 N/kg, equivalent to the acceleration of free fall.
The gravitational field strength varies depending on the mass and radius of the celestial body.

Using a Balance

A balance can be used to compare the weights of two objects.
Because the gravitational field strength on Earth is constant, a balance can also be used to measure the mass of an object.

Friction in Fluids

Gases and liquids are known as fluids.
Friction acts on objects moving through fluids, referred to as drag.
Air resistance is a type of drag that slows down the motion of an object through air.

Acceleration of Freefall

In the absence of air resistance, all objects fall with the same acceleration, known as acceleration of freefall (g) or acceleration due to gravity.
The acceleration of freefall is approximately 9.8 m/s² near the Earth's surface.
The acceleration due to gravity increases an object's velocity by 9.8 m/s for every second it falls.

Terminal Velocity

Objects falling through fluids experience two forces: weight and friction (e.g., air resistance).
The force of air resistance increases with speed.
Terminal velocity is the constant speed reached when the force of air resistance equals the weight force, resulting in zero acceleration.
When a skydiver opens their parachute, the surface area increases, causing increased air resistance and slowing their fall.
A new, slower terminal velocity is reached when the forces balance out again.

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Description

Explore the concepts of mass and weight, and understand the differences between these two quantities. This quiz covers gravitational field strength and how to use a balance to measure mass. Test your knowledge and see how these principles apply in physics.