### 2 or more forces exerted on an object are________ if their effects cancel each other and the do not cause a change in the object's motion

balanced forces

### any time the forces acting on an object are unbalanced, the net force is not zero and the motion of the object changes

...

### if the net force acting on an object is zero, the object remains at rest, or if the object is already moving, continues to move in a straight line with constant speed

Newton's first law of motion

### the force that brings nearly everything to a stop is ____, which is the force that acts to resist sliding bw 2 touching surfaces

friction

### ____ slows down an object that slides... due to the microscopic roughness of 2 surfaces..... produced when the brake pads in a car's brakes rub against the wheels

sliding friction

### _____makes a wheel or tire turn... occurs bw the ground and the part of the tire touching the ground... keeps tire from slipping on the ground...

rolling friction

### _________ connects force, acceleration, and mass.... an object acted upon by a force will accelerate in the direction of the force

Newton's 2nd Law of Motion

### Acceleration Equation =

acceleration (in meters/second) = net force (Newtons)/ mass (in kilograms) ........ a = Fnet/m

### ______ is the point in an object that moves as if all the object's mass were concentrated at that point

center of mass

### according to _____________, forces always act in equal but opposite pairs... for every action there is an equal but opposite reaction

Newton's 3rd Law of Motion

### pressure equation =

pressure (in pascal's) = force (in newtons) / area (in meters squared) ....... P = F/A

### why does an object sink?

if the weight of the object is greater than the buoyant force, the net force on the object is downward and it sinks

### if the buoyant force is equal to the object's weight, the forces are balanced and the object's float

...

### the buoyant force on an object is equal to the weight of the fluid it displaces

Archimedes Principle

### when a force is applied to a fluid in closed container, the pressure in the fluid increases everywhere by the same amount

Pascal's Principle

### when the speed of a fluid increases, the pressure exerted by the fluid decreases

Bernoulli's Principle

### energy that is safer and cause less harm to the environment.... include solar, wind, and geothermal energy

alternative resources

### the sum of the kinetic and potential energy of all the molecules in an object is the _____ of the object

thermal energy

### ____ is thermal energy that is transferred from one object to another when the objects are at diffrent temperatures

heat

### this transfer of thermal energy by the movement of molecules from one part of a material to another

convection

### an object is a measure of how hard it is to stop the object, and it depends on the object's mass and velocity

momentum

### the total momentum of objects that collide is the same before and after the collision

law of conservaition of momentum