Homeroom-SIT IN YOUR ASSIGNED

SEAT! NO ELECTRONICS!!

Warm-up A scientist noticed that all of the offspring of a bacteria are

identical to the parent. However, in dogs, the offspring are all different. What most likely caused this to occur?

a) Bacteria produced offspring through asexual reproduction, while the dog produced offspring through sexual reproduction.

b) Bacteria produced offspring through sexual reproduction, while the dog produced offspring through asexual reproduction.

c) Both bacteria and the dog produced offspring through asexual reproduction.

d) Both bacteria and the dog produced offspring through sexual reproduction.

Force and Net Force•Force is a push

or a pull on an object.

•Net force is the total force on an object.

Unbalanced ForceBalanced Force

• Unbalanced Force can cause an object to move, stop moving, or change direction.

•The balanced forces are the forces in equal and opposite directions.

•The balanced forces are the forces in equal and opposite directions.

Forces change motion.

•HMM…. Can you see the unbalanced force here?

•HMM…. Can you see the unbalanced force here?

•

Inertia –An object at rest will stay at rest unless acted upon by an outside force.

–Inertia is every objects resistance to change its motion.

Newton’s First LawNewton’s First Law

Greater mass

means

Greater inertia

Greater mass

means

Greater inertia

Newton’s Second Law

• The acceleration of an object is directly proportional to the net force acting on the object and inversely proportional to the object’s mass.

Force=mass x accelerationForce=mass x accelerationF=m x aF=m x a

Force and mass determine acceleration

.

Luke! Use the mass times

the acceleration!

Luke! Use the mass times

the acceleration!

How much Force was required to make a 2000kg car accelerate at

5m/s/s?

1 2 3

33% 33%33%

1. 400N

2. 0.001N

3. 10,000N

• Force=Mass x acceleration• F=ma• F=2000kg x 5m/s/s• a= 10,000N or kgxm/s/s

4 Types of Friction• The 4 types of friction are: 1. Sliding friction (strongest)2. Rolling friction 3. Fluid friction (weakest).4. Static friction

• What type of friction?

•What type of friction

?

•What type of friction

?

•What type of friction?

•What type of friction?

What type of friction?What type of friction?

2 Factors of Friction

•1-Type of surface. •2-How hard the two surfaces push together.

•

Which type of hockey has more friction?

Which type of hockey has more friction?

Air Resistance and Weight

• Air resistance is a type of fluid friction on falling objects. Weight is the force of gravity on an object at the surface of the Earth.

Law of Universal Gravitation

•Gravity acts between all objects in the universe.

Gravity Between Objects• The force of gravity between objects

increases with greater mass and decreases with greater distance.

•Gravity is the force that pulls objects toward the Earth- acceleration due to gravity is 9.8m/s/s.

Newton’s Third law• If an object exerts a force

on another object, the second object, exerts an equal force in the opposite direction.

Momentum• The momentum of an object

is the product of its mass and velocity.

• In other words:

Momentum = mass x velocityMomentum = mass x velocity

•Kg x m/s•Kg x m/s

COLLISIONS

Law of Conservation of Momentum

•The total momentum of the objects that interact does not change.