Chapter 12

12.1 Definitions

100

Force

a push or pull that acts on an object

200

Friction

a force that opposes the motion of objects that touch as they move past each other.

300

•Projectile motion

is the motion of a falling object (projectile) after it is given an initial forward velocity.

400

•Gravity

is a force between any two masses.

500

Air resistance

 is fluid friction acting on an object moving through the air.

Frictions

100

What is Static Friction

•is the friction force that acts on objects that are not moving.

200

Give me an example of Sliding friction

anything that slides

300

Give me an example of rolling friction

Anything that rolls

400

What is Fluid friction

opposes the motion of an object through a fluid- liquid or gas.

500

Which way does friction act?

in the direction opposite of motion

12.2 Definitions

100

the tendency of an object to resist a change in its motion.

•Inertia

200

Net force divded by Mass

Acceleration

300

•Mass

is the amount of matter an object contains.

400

the force of gravity acting on an object.

–-measured in Newtons (N)

•Weight

500

Law of Inertia

•The state of motion of an object does not change as long as the net force acting on the object is zero.

•

Acceleration Math

100

•A car with a mass of 1000 kg accelerates. If the net force on the car is 4000 N, what is the car’s acceleration?

4 m/s2

200

•A boy pushes forward a cart of groceries with a total mass of 40.0 kg. What is the acceleration of the cart if the net force on the cart is 60.0 N?

1.5 m/s2

300

•What is the upward acceleration of a helicopter with a mass of 5000 kg if a force of 10,000 N acts on it in an upward direction?

2 m/s2

400

•An automobile with a mass of 1200 kg accelerates at a rate of 3.0 m/s2. What is the net force acting on the automobile?

3600 Newtons

500

•A 25-N force accelerates a boy on a skateboard at          0.5 m/s2. What is the mass of the boy and the skateboard?

50 kg

12.3

100

What are the direction and sizes of action and reaction forces?

•These two forces are equal in size and opposite in direction.

200

What is the momentum Formula?

M = mass x acceleration

300

•Calculate the momentum of an object which has a mass of 0.26 kg if it has a velocity of 6.5 m/s.

1.69 Newtons

400

What vocab term is: if no net force acts on a system, then the total momentum of the system does not change.

•Law of conservation of momentum,

500

•Which has more momentum, a 46 gram rock with a speed of 30.0 meters per second, or a 8.0-kilogram brick with a speed of 3.0 meters per second?

Brick