Physics Hooke's Law Quiz

Questions and Answers

Define thinking distance and mention two factors that can increase it.

Thinking distance is the distance traveled during the time a driver takes to react and apply the brakes; it can be increased by greater speed and slower reaction times due to distractions or alcohol.

How does air resistance affect a falling object in a uniform gravitational field?

Air resistance increases as the object falls, reducing the resultant force and consequently decreasing its acceleration.

What is the relationship described by Hooke's Law?

Hooke's Law states that the extension of a spring is directly proportional to the force applied to it, until the elastic limit is reached.

Explain what is meant by elastic deformation.

Elastic deformation occurs when an object returns to its original shape after the load is removed, such as a spring stretching under normal use. Signup and view all the answers

What is the stopping distance of a vehicle?

Stopping distance is the sum of the thinking distance and the braking distance. Signup and view all the answers

What factors could increase a vehicle's braking distance?

Factors that increase braking distance include greater speed and poor road or car conditions, such as worn tires or brake pads. Signup and view all the answers

What principle explains the moment of a force?

The moment of a force is the product of the force and the perpendicular distance from the pivot point to the line of action of the force. Signup and view all the answers

What happens to the motion of a body when the forces acting on it are balanced?

When forces are balanced, the body remains in a state of equilibrium and its motion does not change. Signup and view all the answers

Can an object's momentum be conserved when external forces act on it?

No, momentum is only conserved in a closed system where no external forces act on the bodies involved. Signup and view all the answers

What is meant by the equilibrium of forces?

Equilibrium of forces occurs when the total force acting on an object is zero, resulting in no change in motion. Signup and view all the answers

Study Notes

Hooke's Law

States the relationship between force and extension in springs: ( F = kx ), where ( F ) is force, ( k ) is the spring constant, and ( x ) is extension.
Elastic deformation follows Hooke's law until the limit of proportionality is reached, where the behavior becomes non-linear.
Gradient of the linear force-extension graph represents the spring constant ( k ).

Force-Extension Graphs

Linear graphs demonstrate elastic deformation; deviations indicate non-compliance with Hooke's law leading to eventual fracture.
Non-linear (curved) force-extension graphs indicate deformation not following Hooke's law.

Moment of a Force

Defined as the measure of a force's turning effect, calculated as ( \text{moment} = \text{force} \times \text{perpendicular distance from pivot} ) (Nm).
Objects are in equilibrium when the sum of clockwise moments equals the sum of anticlockwise moments, resulting in no resultant force.

Momentum

Momentum defined by the equation ( p = mv ), where ( p ) is momentum, ( m ) is mass, and ( v ) is velocity; units are kg·m/s.
Force exerted by an object equals the change in momentum over time: ( F = \frac{\Delta p}{t} ) or ( F = \frac{mv - mu}{t} ).
Safety features in cars, such as seatbelts, extend the time taken to come to rest, reducing force during a collision.

Forces, Movement, and Types

Forces measured in Newtons (N) can change speed, shape, or direction.
Types of forces include gravitational and electrostatic; friction opposes motion and generates heat.
Resultant force found by adding/subtracting forces along the same line based on direction.

Newton's Laws of Motion

First Law: An object remains at constant velocity unless acted on by a resultant force.
Second Law: Force is the product of mass and acceleration: ( F = ma ).
Third Law: Every action force has an equal and opposite reaction force.

Mass and Weight

Mass quantifies the amount of matter in an object, measured in kilograms (kg).
Weight, the force exerted by gravity on a mass, is calculated as ( W = mg ); gravitational field strength on Earth is approximately 10 N/kg.

Terminal Velocity

Describes the motion of an object in free fall where weight and air resistance balance.
Initially, only weight acts; acceleration increases speed, increasing air resistance until equilibrium is reached, resulting in no acceleration.

Braking Distance and Thinking Distance

Thinking distance: the distance covered between realizing the need to stop and pressing the brakes, affected by speed, reaction time, and distractions.
Braking distance: the distance from pressing the brakes to a complete stop, influenced by speed, mass, and road/car conditions.
Total stopping distance equates to the sum of thinking distance and braking distance.

Deformation

Elastic deformation allows an object to return to its original shape upon load removal, exemplified by springs under normal conditions.

Description

Test your understanding of Hooke's Law and the behavior of springs in this quiz. Explore the concepts of linear and non-linear force-extension graphs, as well as the significance of the spring constant. Challenge yourself with questions that delve into the limits of proportionality and elastic deformation.