April 16, 2019

Friday, March 15th• In Class

> Begin Force Notes (4 slides)

• Practice

• Upcoming> Ch. 12 Vocabulary due 3/20> Quiz Wednesday

PhySci

ForcesChapter 11.3 & 12

April 16, 2019

I. What is a Force?

• Push or Pull exerted on an object> MAY change the motion of an object

• Has a magnitude & direction> measured in Newtons (N)

II. Net Force

• Balanced> all forces create net force of ZERO

– No change in motion "or" Constant Motion » (No Acceleration)

• Unbalanced> Net force = NOT Zero

– Change in Motion» (Acceleration)

> Combination of all forces acting on an object– Forces added up = Net Force

April 16, 2019

III. Friction

– force opposing motion between surfaces in contact

April 16, 2019

IV. Types of Friction

• Static Friction:force resisting initial motion between 2 surfaces at rest> Force applied, but object

does not move

• Kinetic Friction: > Friction between moving surfaces

– Sliding or Rolling» Sliding > Rolling

Monday, March 18th• In Class

> Force Notes (2 slides)> Worktime on pg. 64-68

• Practice> Pg. 64-68, Practice with F = m x a > Pg. 72, Review Newton's 1st & 2nd Laws

• Upcoming> Ch. 12 Vocab due Wednesday (3/20)> Quiz Wednesday

PhySci

April 16, 2019

V. Newton's First Law

• An object at rest stays at rest, & an object in motion stays in motion (in a straight line at a constant speed) unless it is acted on by an unbalanced force.

• Also known as INERTIA > tendency of an object to

resist a change in motion unless an outside force acts on the object– related to the mass of

the object

VI. Newton's Second Law

• The unbalanced force acting on an object equals the object's mass times its acceleration.

• If forces are equal, a larger mass accelerates less.

• If masses are equal, a greater force produces greater acceleration

April 16, 2019

• How much force is required to accelerate a 72,000 g rider and a 210 kg motorcycle forward at 4.0 m/s2?

Tuesday, March 19th• In Class

> Review Newton's 1st & 2nd Law> Worktime on pg. 64-68

• Practice> Pg. 64-68> Pg. 72, Review Newton's 1st & 2nd Laws

• Upcoming> Quiz Wednesday

– Friction & Newton's 1st 2 Laws

PhySci

April 16, 2019

Wednesday, March 20th• In Class

> Study for Quiz & Check 12 Vocabulary> Ch. 12 Quiz #1 Tomorrow

• Practice

• Upcoming

PhySci

Thursday, March 21st• In Class

> Ch. 12 Quiz #1> Introduce Parachute Lab

– Pick groups

• Practice

• Upcoming

PhySci

April 16, 2019

Monday, April 1st• In Class

> Review Newton's 1st & 2nd Law> Worktime on Parachute planning and Prep for workday> Quizzes passed back

• Practice> Pg. 64-68> Pg. 72, Review Newton's 1st & 2nd Laws

• Upcoming

PhySci

• Explain the following situations using Newton's 1st & 2nd Laws of motion.

> Skydiver accelerating towards the ground

> Skydiver falling at constant velocity

> Skydiver slowing down as they open their parachute

April 16, 2019

Wednesday, April 3rd• In Class

> Weight & Gravity Notes (3 slide)> Weight Practice Worksheet

– due Monday

• Practice/Homework> Weight & Gravity Worksheet due Monday

• Upcoming> Quiz Monday

– Forces, 1st & 2nd Law, Weight & Gravity

PhySci

VII. Weight vs. Mass

• Mass: amount of matter something contains (kg)> does not change when location changes (moon?)

• Weight: measurement of Force of gravity on object. (N)> changes with location

– Weight = m x g (g = acceleration due to gravity)

April 16, 2019

VIII. Law of Universal Gravitation

• All objects attract each other through force of gravity. > explains motion of planets & why objects fall to surface> Newton developed equation to describe....

• F = gravitational force• m1 & m2 = masses of the 2 objects• d = distance between the two objects • G = constant (always has the same value)

> 6.67 x 10-11

April 16, 2019

Monday, April 8th• In Class

> Free Fall Notes (2 Slides)> Work on New Parachute

• Practice

• Upcoming> Quiz Thursday

PhySci

IX. Free Fall

• Motion of an object when only the only force acting on it is gravity.> Without Air Resistance, objects accelerate at the same

rate regardless of their mass. Why?

• A heavy object has a greater gravitational force than a light object does.

• However, it is harder to accelerate a heavy object than a light object because the heavy object has more mass.

April 16, 2019

X. Terminal Velocity

• When air resistance and the force of gravity (weight) are equal, the object stops accelerating and reaches its maximum velocity.

Tuesday, April 9th• In Class

> Review Free Fall & Watch Video> Finish Rebuild of Parachute

• Practice/Homework/Upcoming > Test Parachute #2 tomorrow

PhySci

April 16, 2019

Monday, April 15th• In Class

> Projectile Motion & 3rd Law Notes> Finish & Hand In Parachute Lab

• Practice> Pg. 64-68, Practice with F = m x a > Pg. 72, Review Newton's 1st & 2nd Laws> Weight & Mass Worksheet

• Upcoming> CH. 12 Test Thursday

PhySci

VII. Projectile Motion• Curved path of motion (2 components)

> Horizontal: velocity > Vertical: accelerate down (gravity)

• Orbits can be explained using projectile motion

April 16, 2019

VIII. Newton's Third Law

• When one object exerts a force on a second object, the 2nd object exerts a force EQUAL IN SIZE and OPPOSITE IN DIRECTION on the first object. > for every action force, there is an equal & opposite

reaction force

• Forces always occur in pairs (action & reaction)

• The paired forces do NOT act on the same object

• Equal forces don't always have equal effects

Tuesday, April 16th• In Class

> Momentum Notes> Practice Momentum & Study for Test

• Practice> Pg. 79: Review 3rd Law> Pg. 80-84: Momentum Practice #1-18> Pg. 64-68, Practice with F = m x a > Pg. 72, Review Newton's 1st & 2nd Laws> Weight & Mass Worksheet

• Upcoming> CH. 12 Test Thursday

PhySci

April 16, 2019

IX. Momentum

• Momentum = Mass (kg) x Velocity (m/s)> Units =

• Momentum increases as mass and/or velocity increases> Stopping cars of different speeds/

mass?

• Ex: What is momentum of a 6kg bowling ball rolling at 22.4 mph?

X. Law of Conservation of Momentum

• Total momentum of two or more objects after a collision is THE SAME as it was before the collision> Total amount of momentum is conserved