Chapter 2

43 terms

force

a push or pull on an object; needed to change an object's motion

strength; direction

force has both____________and _______________. (; between)

net force

forces combined on the same object

unbalanced forces

have a net froce greater than zero and will change an object's motion

balanced forces

equal forces acting in opposite directions, have a net force equal to zero and will not change an object's motion

unbalanced forces

what type of force can change an object's motion?

no

can forces acting on different objects be added together?

inertia

the tendency of an object to resist change in its motion

mass

amount of matter in an object

mass

what does the amount of inertia an object have depend on?

Newton's first law of motion

which law is this?
an object at rest will remain at rest and an object moving at constant velocity will continue moving at constant velocity unless acted upon by an unbalanced force

the law of inertia

what is newton's first law of motion also known as?

the net force of an object is equal to the product of its acceleration and its mass

what is newton's second law of motion; F= MA

Newton (kg x meters per second per second)

what unit is used to measure force?

Friction

force that one surface exerts on another when they rub against each other; acts in a direction opposite to the direction an object is moving

the types of surfaces involved in how hard they push together

what does the strength of friction depends on

sliding friction

occurs when solid surfaces slide over each other

rolling friction

occurs on an object roles over surface

fluid friction

occurs when an object moves through a liquid or gas

sliding friction

what friction needs the most force to overcome?

Gravity

the force that pulls objects towards each other

Free fall

when the only force acting on an object is gravity, what is that called?

9.8 m/s squared

if an object is in freefall, how fast does it accelerate regardless of the mass?

Projectile

any object that is thrown

air resistance

objects falling through air experiences a type of fluid friction, which is called_______

terminal velocity

the greatest velocity that the object reaches

weight

the force of gravity, or a person or object at the surface of a planet

weight = mass × acceleration

what is the formula for weight?

The Newton because weight is the force of gravity

What is the unit of measurement for weight and why?

The force of gravity acts between objects in the universe

What does the law of universal gravitation state?

The mass of the objects and the distance between the objects

what does the strength of gravity depend on?

Newton's third law of motion

what is the law that states:
if one object exerts a force on another object, then the second object exerts a force of equal strength in opposite direction on the first object

the forces are acting on two different objects, they have to be acting upon the same object to be able to be added up

why can action and reaction forces not be added up?

Momentum

the product of an objects mass and velocity

momentum = mass times velocity (P=MV)

what is the formula for momentum? (write out the word for the symbol: ex. plus for +)

Kilograms times meters per second per second

what is the unit of measurement for momentum? (write everything in words: ex. milliliters plus killoleters per millenium)

Same as its velocity

what direction this momentum facing?

The total momentum of the objects and an interaction is the same before and after the interaction

what is the law of conservation of momentum state?

Because the gases that expel the downward force exerts an equal but opposite force in an upward direction (in other words: a rocket pushes gas DOWN at the same speed they need to be going UP, because of the 3rd law, it shoves them into the air)

why can a rocket rise into the air?

Thrust

the upward pushing force is

Greater

the thrust must be_________ than the downward pull

Satellite

any object that travels around another object in space

centripetal force

the force that causes an object to move in a circle; means" center seeking"

Example: