Physics Chapter 12 Assessment

Questions and Answers

What is not a force?

Friction

Gravity

Momentum (correct)

Weight

You push on the box and are unable to move it. What force opposes your push?

Rolling friction

Static friction (correct)

Sliding friction

Air resistance

Air resistance depends on _____

The velocity of a moving object (correct)

The inertia of a moving object

The weight of a moving object

The mass of a moving object

What force besides gravity acts on a projectile?

Air resistance Signup and view all the answers

Newton's first law of motion is sometimes called the law of _____.

Inertia Signup and view all the answers

A change in which of the following affects the weight of an object?

Acceleration due to gravity Signup and view all the answers

Which represents Newton's second law?

a = F/m Signup and view all the answers

Complete the sentence. For every action there is a _____

Reaction force Signup and view all the answers

Momentum depends upon _____

Mass and velocity Signup and view all the answers

What force holds the nucleus together?

Strong nuclear Signup and view all the answers

Suppose two 4 Newton forces act on an object in the same direction. What is the net force on the object?

8 Newtons Signup and view all the answers

Five different forces act on an object. Is it possible for the net force on the object to be 0? Explain.

Yes, all of the forces can cancel one another. Signup and view all the answers

What happens to an object when an unbalanced force acts on it?

Acceleration Signup and view all the answers

You push harder and harder on a box until it began sliding across the floor. Which was the stronger of the forces acting on the block: static friction or sliding friction?

Static Signup and view all the answers

Explain why a falling object subjected to Earth's gravity does not continue to accelerate forever.

Terminal Velocity Signup and view all the answers

What is the difference between mass and weight?

Weight depends on gravity, mass is a measure of inertia. Signup and view all the answers

What is an action-reaction pair?

Newton's Third Law Signup and view all the answers

What must you know to determine which of two vehicles traveling at the same velocity has the greater momentum?

Mass Signup and view all the answers

What force is responsible for your socks sticking together after they've been in a clothes dryer?

Electric force Signup and view all the answers

What particles do the strong and weak nuclear forces act on?

Strong: protons and neutrons; weak: all particles. Signup and view all the answers

What force is responsible for the orbits of the planets in the solar system?

Gravitational force Signup and view all the answers

When shooting an arrow at the target, why is it advisable to aim above the target rather than directly at it?

It follows a projectile path; gravity alters its route, so one needs to account for that. Signup and view all the answers

The moon's gravity is only one sixth that of Earth. Explain how the weight of an object differs between the two locations.

Objects weight is six times greater on Earth; however, its mass is the same in both locations. Signup and view all the answers

When a tennis player practices by hitting the ball against the wall, which of Newton's laws of motion is the player making use of?

Third Law when hit on the wall; Second Law when force from racket or wall is applied to it. Signup and view all the answers

Consider two rocks with masses of 1 and 10 kilograms. What is the relation between their inertias, masses, and weights?

The inertia, mass, and weight of the 10 kg rock are 10 times greater than that of the 1 kg rock. Signup and view all the answers

On Earth during the fuel economy test of a sports car, why does the car achieve more miles per gallon of gasoline when its convertible top is down?

Air resistance is greatly increased. Signup and view all the answers

What are the two ways in which the acceleration of an object can be increased?

Increasing the force applied or decreasing the mass of the object will increase the acceleration of the object. Signup and view all the answers

A 100 kilogram crate sliding on the floor is brought to a stop by a 25 Newton force. What is the deceleration of the crate?

0.25 m/s² Signup and view all the answers

What is the momentum of an 80 kilogram runner moving at the speed of 2.5 m/s?

200 kg m/s Signup and view all the answers

What is the weight on Earth of a girl with a mass of 30 kilograms? The acceleration due to gravity on Earth is 9.8 meters per second squared.

290 N Signup and view all the answers

Study Notes

Forces and Motion

Momentum is not a force; it is dependent on mass and velocity.
Static friction opposes the initial push on an object, preventing its movement.
Air resistance increases with the velocity of a moving object, impacting its motion.
Besides gravity, air resistance is a significant force acting on projectiles.

Newton's Laws of Motion

Newton's first law is known as the law of inertia, describing an object's resistance to changes in motion.
Newton's second law is represented as a = F/m, correlating acceleration with force and mass.
According to Newton's third law, for every action there is an equal and opposite reaction.

Weight and Gravity

Weight changes based on the acceleration due to gravity; mass remains constant regardless of location.
The moon’s gravity is one-sixth that of Earth, making weights different while masses stay the same.

Characteristics of Forces

The net force is the overall force acting on an object, and multiple forces can cancel to create a net force of zero.
Forces acting in the same direction are additive; two 4 Newton forces give a net force of 8 Newtons.

Projectile Motion

A projectile follows a curved path due to gravity, requiring adjustments in aim when targeting.

Practical Applications of Forces

The strong nuclear force holds protons and neutrons together in atomic nuclei.
Gravitational force keeps planets in orbit, essential for the stability of the solar system.

Miscellaneous Concepts

Electric force can cause objects like socks to stick together.
The inertia of an object is directly proportional to its mass; a 10 kg object exhibits ten times the inertia of a 1 kg object.
Air resistance influences fuel economy in vehicles, affecting performance based on their aerodynamic shape.

Acceleration Factors

An object's acceleration can be increased by either applying more force or reducing its mass.
Deceleration can be calculated; for example, a 100 kg crate decelerating under a 25 Newton force results in 0.25 m/s².

Calculations

The momentum of an object is calculated using its mass and velocity, e.g., an 80 kg runner at 2.5 m/s has a momentum of 200 kg m/s.
The weight of an object is calculated by multiplying its mass by the acceleration due to gravity, e.g., a girl with a mass of 30 kg weighs approximately 290 N on Earth (30 kg × 9.8 m/s²).

Studying That Suits You

Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

Description

Test your knowledge with these assessment questions from Physics Chapter 12. This quiz covers key concepts related to forces, including friction and air resistance. Perfect for students preparing for exams or revising essential concepts!