Notes- Concept 1-3-Describing Motion,Acceleration, Newton's Laws-Allen
Force
Definition: Force (F) is a push or pull that one object exerts on another.
Measurement: Forces are measured in Newtons (1 N = 1 kg*m/s²).
Effects on Motion: Forces can cause a change in an object's motion. More than one force can act on an object simultaneously.
Net Force: Combination of forces acting on an object.
Example: If one force is 2 N and another is 3 N to the left, the net force is 3 N.
Page 2: Types of Forces
Balanced Forces: Equal in size and opposite in direction; do not change motion (Net Force = 0).
Example: 4 N left balanced by 4 N right; Net Force = 0 N.
Page 3: Unbalanced Forces
Unbalanced Forces: Not equal in size or direction; cause motion in the direction of the greater force.
Example: 2 N right and 7 N left combine for a Net Force of 6 N to the right.
Newton's 1st Law of Motion (Page 4)
Principle: An object will maintain constant velocity unless acted upon by a net force.
Objects in motion tend to stay in motion; objects at rest stay at rest unless a force acts on them.
Inertia (Page 5)
Definition: Inertia is the tendency of an object to resist changes in motion.
Mass & Inertia: More mass = more inertia.
Real-Life Example: When braking, the body continues moving forward, necessitating seatbelt use for safety.
Forces Changing Motion (Page 6)
Friction: Resistance encountered when two objects are in contact.
Air Resistance: The resistance an object faces moving through the air.
Gravity: The attractive force that pulls objects towards one another, specifically toward Earth at 9.8 m/s².
Factors Affecting Friction (Page 7)
Surface Roughness: Rougher surfaces have greater friction due to more microwelds (microscopic bumps).
Force of Contact: Greater force pushing objects together increases friction.
Surface Area: Increased surface area of contact increases friction.
Types of Friction (Page 8)
Static Friction: Between two surfaces that are not moving past each other.
Sliding Friction: Between two surfaces moving past each other.
Rolling Friction: Between a rolling object and the surface it rolls on.
Air Resistance (Page 9)
Definition: A form of friction acting in air (drag).
Determinants:
Speed: Higher speeds increase resistance.
Size: Larger objects encounter more resistance.
Shape: Flatter objects experience greater resistance.
Law of Universal Gravitation (Page 10)
States that any two masses attract each other based on:
Mass: Larger mass results in greater gravitational attraction.
Distance: Closer distance leads to stronger attraction.
Gravity (Page 11)
The gravitational force pulls objects downward, causing an acceleration of 9.8 m/s², regardless of mass (ignoring air resistance).
Terminal Velocity (Page 12)
The maximum speed a falling object achieves when the force of gravity equals the force of air resistance; at this point, net force = 0, causing no further acceleration.
Example: In humans, can reach speeds of 55 m/s or 118.06 mi/hr.
Newton's 2nd Law of Motion (Page 13)
Principle: A net force acting on an object causes it to accelerate in the direction of the force.
Greater mass requires greater force for acceleration.
More net force leads to higher acceleration.
Force-Mass-Acceleration Relationship (Page 14)
Formula: F = ma
Where:
F = Force (in Newtons)
m = Mass (in kg)
a = Acceleration (in m/s²)
Example: Pushing a sled: 40 N force acts on an 80 kg sled resulting in an acceleration of 0.5 m/s².
Weight (Page 15)
Definition: The gravitational force on an object. Weight can be calculated using F = ma, with g = 9.8 m/s² for the acceleration due to gravity.
Example: Weight of a 42 kg suitcase = 411.6 N.
Weight vs. Mass (Page 16)
Mass: The amount of matter in an object, unaffected by location.
Weight: The gravitational force on an object, which changes with location (e.g., weight is 1/6 of its weight on the Moon).
Example: Weight on Jupiter would be more than twice as much as on Earth.
Newton's 3rd Law of Motion (Page 18)
Principle: For every action, there is an equal and opposite reaction.
Example: Jumping on a trampoline results in the trampoline exerting an upward force on the jumper.
Law of Conservation of Momentum (Page 19)
Definition: Momentum (p) is mass in motion.
Formula: p = mv
Where:
m = mass (in kg)
v = velocity (in m/s)
Momentum is transferred during collisions without being created or destroyed.
Transfer of Momentum (Page 20)
Due to equal and opposite forces in collisions (Newton's 3rd Law), momentum is conserved; it is transferred but never lost.
Momentum Calculations Examples (Pages 21-22)
Example 1: Car with mass 1300 kg traveling at 28 m/s:
Calculation: p = (1300 kg)(28 m/s) = 36,400 kg*m/s.
Example 2: Collision between two balls to determine mass using conservation of momentum.
Quick Definitions:
Force
Definition: Force (F) is a push or pull that one object exerts on another.
Measurement: Measured in Newtons (1 N = 1 kg*m/s²).
Effects on Motion: Forces can cause a change in an object's motion; multiple forces can act simultaneously.
Net Force: Combination of forces acting on an object.
Example: If one force is 2 N and another is 3 N to the left, the net force is 3 N.
Types of Forces
Balanced Forces: Equal in size and opposite in direction; do not change motion (Net Force = 0).
Example: 4 N left balanced by 4 N right; Net Force = 0 N.
Unbalanced Forces
Unbalanced Forces: Not equal in size or direction; cause motion in the direction of the greater force.
Example: 2 N right and 7 N left combine for a Net Force of 6 N to the right.
Newton's 1st Law of Motion
Principle: An object will maintain constant velocity unless acted upon by a net force.
Objects in motion stay in motion; objects at rest stay at rest unless a force acts on them.
Inertia
Definition: Inertia is the tendency of an object to resist changes in motion.
Mass & Inertia: More mass = more inertia.
Real-Life Example: When braking, the body continues moving forward; necessitates seatbelt for safety.
Forces Changing Motion
Friction: Resistance when two objects are in contact.
Air Resistance: Resistance an object faces moving through air.
Gravity: Attractive force pulling objects towards each other (specifically towards Earth at 9.8 m/s²).
Factors Affecting Friction
Surface Roughness: Rougher surfaces have greater friction.
Force of Contact: Greater pushing force increases friction.
Surface Area: Increased contact area increases friction.
Types of Friction
Static Friction: Between surfaces not moving past each other.
Sliding Friction: Between surfaces moving past each other.
Rolling Friction: Between a rolling object and the surface it rolls on.
Air Resistance (Drag)
Definition: A friction force acting in air.
Determinants: Speed, size, and shape of the object influence resistance.
Law of Universal Gravitation
Any two masses attract each other based on mass and distance.
Gravity
Gravitational force pulls objects downward (9.8 m/s²).
Terminal Velocity
Maximum falling speed when the force of gravity equals air resistance (net force = 0).
Newton's 2nd Law of Motion
Principle: A net force causes acceleration in the object's direction.
Formula: F = ma.
Example: 40 N force on an 80 kg sled = 0.5 m/s².
Weight vs. Mass
Mass: Amount of matter; unaffected by location.
Weight: Gravitational force on object; changes with location.
Example: Weight on the Moon vs. Jupiter.
Newton's 3rd Law of Motion
Principle: For every action, there is an equal and opposite reaction.
Example: Jumping on a trampoline.
Law of Conservation of Momentum
Definition: Momentum (p) is mass in motion (p = mv).
Momentum is conserved during collisions.
Force
Definition: Force (F) is a push or pull that one object exerts on another.
Measurement: Measured in Newtons (1 N = 1 kg*m/s²).
Effects on Motion: Forces can cause a change in an object's motion; multiple forces can act simultaneously.
Net Force: Combination of forces acting on an object.
Example: If one force is 2 N and another is 3 N to the left, the net force is 3 N.
Types of Forces
Balanced Forces: Equal in size and opposite in direction; do not change motion (Net Force = 0).
Example: 4 N left balanced by 4 N right; Net Force = 0 N.
Unbalanced Forces
Unbalanced Forces: Not equal in size or direction; cause motion in the direction of the greater force.
Example: 2 N right and 7 N left combine for a Net Force of 6 N to the right.
Newton's 1st Law of Motion
Principle: An object will maintain constant velocity unless acted upon by a net force.
Objects in motion stay in motion; objects at rest stay at rest unless a force acts on them.
Inertia
Definition: Inertia is the tendency of an object to resist changes in motion.
Mass & Inertia: More mass = more inertia.
Real-Life Example: When braking, the body continues moving forward; necessitates seatbelt for safety.
Forces Changing Motion
Friction: Resistance when two objects are in contact.
Air Resistance: Resistance an object faces moving through air.
Gravity: Attractive force pulling objects towards each other (specifically towards Earth at 9.8 m/s²).
Factors Affecting Friction
Surface Roughness: Rougher surfaces have greater friction.
Force of Contact: Greater pushing force increases friction.
Surface Area: Increased contact area increases friction.
Types of Friction
Static Friction: Between surfaces not moving past each other.
Sliding Friction: Between surfaces moving past each other.
Rolling Friction: Between a rolling object and the surface it rolls on.
Air Resistance (Drag)
Definition: A friction force acting in air.
Determinants: Speed, size, and shape of the object influence resistance.
Law of Universal Gravitation
Any two masses attract each other based on mass and distance.
Gravity
Gravitational force pulls objects downward (9.8 m/s²).
Terminal Velocity
Maximum falling speed when the force of gravity equals air resistance (net force = 0).
Newton's 2nd Law of Motion
Principle: A net force causes acceleration in the object's direction.
Formula: F = ma.
Example: 40 N force on an 80 kg sled = 0.5 m/s².
Weight vs. Mass
Mass: Amount of matter; unaffected by location.
Weight: Gravitational force on object; changes with location.
Example: Weight on the Moon vs. Jupiter.
Newton's 3rd Law of Motion
Principle: For every action, there is an equal and opposite reaction.
Example: Jumping on a trampoline.
Law of Conservation of Momentum
Definition: Momentum (p) is mass in motion (p = mv).
Momentum is conserved during collisions.