50 terms

force

a push or pull that acts on an object

newton

the force that causes a 1 kilogram mass to accelerate at a rate of 1 meter per second (1m/s2)

net force

the overall force acting on an object, after all the forces are combined

sliding friction

a force that opposes the direction of motion of an object as it slides over a surface

static friction

the friction force that acts on objects that are not moving

rolling friction

the friction force that acts on rolling objects

fluid friction

opposes the motion of an object moving through the air

air resistance

fluid friction acting on an object moving through the air

gravity

a force that acts between any two masses

terminal velocity

the constant velocity of a falling object when the force of air resistance equals the force of gravity

projectile motion

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

inertia

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

mass

a measure of the inertia of an object and depends on the amount of matter the object contains

weight

the force of gravity acting on an object

momentum

the product of an object's mass and it's velocity

law of conservation of momentum

if no net forces act on a system, then the total momentum of the system does not change.

electromagnetic force

associated with charged particles. Electric force and magnetic force are the only forces that can both attract and repel

strong nuclear force

a powerful force of attraction that acts only on the neutrons and protons in the nucleus, holding them together

weak nuclear force

an attractive force that cacts only over a short range

gravitational force

an attractive force that acts between two masses

centripetal force

the center-directed force that contunuoulsy change the direction of an object to make it move in a circle

mass, distance

gravity increases as ___ is increased and ___ is decreased

9.8 m/s2

what is the acceleration due to gravity?

first

The state of motion of an object does not change as long as the net force acting on the object is zero. What law of Newton's is this?

acceleration=net force % mass

what is the equation for newton's second law?

weight= mass * acceleration

what is the formula for weight?

third

whenever one object exerts a force on a second object, the second object exerts an equal and opposite force on the first object. what law is this?

momentum = mass * velocity

what is the equation for momentum?

speed, direction

a force can cause a resting object to move, or it can accelerate a moving object by changing the objects ___ or ____

balanced

when the net forces are ____, the net force is zero and there is no change in the object's motion

accelerates

when an unbalanced force actos on an object, the object ____

static, sliding, rolling, fluid

what are the four types of friction? (greatest to lowest)

gravity

Earth's ___ acts downward toward the center of Earth

gravity, air resistance

___ causes objects to accelerate downward, whereas ___ acts in the direction opposite to the motion and reduces acceleration

initial forward velocity, downward vertical force

the combination of an _____ and the ____ of gravity causes the ball to follow a curved path

both

two coins are knocked off a table at the same time by different forces. Which coin will hit the floor first?

momentum

an object has a large ____ if the product of its mass and velocity is large

closed system

in a _____, the loss of momentum of one object equals the gain in momentum of another object-momentum is conserved

electric, magnetic

____ force and ___force are the only forces that can both attract and repel

strong, weak

two forces, the ___ nuclear force and the __ nuclear force, act within the nucleus to hold it together

law of universal gravitation

Newton's _________ states that every object in the universe attracts every other object

accels

the more the force the greater objects ____

motion

when you change an unbalanced force, you can change an object's ____

speed

when you change a object's magnitude, you change the object's ____

spring scale

what scale measures how much things weigh? **in newtons**

acceleration

a change in velocity and direction causes a change in what?

friction

___moves in the opposite direction

strength

what's another word for magnitude?

unbalanced force

an ___ is a forcfe that results when the net force acting on an object is not equal to zero

electromagnetic, strong nuclear, weak nuclear, gravitational

what are the four main universal forces?