Physical Science Chapter 10 Study Guide Flashcards
A push or pull
Force
How do you describe a force in a way that is similar to describing velocity and Acceleration
A force is described by its strength and direction
SI unit for all forces
Newton
The combo of all forces acting on an object
Net force
When 2 forces are in the same direction what do u do?
Add them together
When 2 forces are in different directions what do u do?
U subtract to find the net force
Goes direction that is bigger in problem
What are forces that r equal but in opposite directions?
Subtract them to get 0N net force. No arrow
Forces acting on an object resulting in a net force and cause a change in the objects motion
Unbalanced forces
Equal forces acting on an object in opposite directions do not change the objects motion
Balanced forces
What two factors determine the strength of a friction force.
How hard the surfaces push together
The types of surfaces involved
Friction opposes motion. Give an example
Treads on a car tire:start moving:start moving
Tennis shoes have treads=help u walk better
Occurs when one solid surface slide over another
Slidling friction
Acts on objects that are not moving. In the opposite direction of the intended motion
Static friction
Occurs when one object rolls over a surface. Easier to overcome than sliding friction
Rolling friction
Occurs when a solid object moves through fluid. Easier to I overcome than sliding friction. Fluid used include oil water or air
Fluid friction
A force that pulls objects toward each other
Gravity
The force if gravity acts between all objects in the universe
Law of universal gravitation
What r the two factors that affect gravity
More mass=more gravity
Distance=as distance between two objects, gravity decreases
Amount of matter in an object
Mass
Gravity in relation to mass
More massive objects exert more gravity
Difference between mass and weight
Mass-(amount of matter) doesn’t vary with the strength of gravity
Weight-a measure of the amount of gravity acting on an object
How does the astronauts weight and mass on earth compare to mass and weight on the moon
Mass stays the same in both places. since gravity is different weight is different
The motion of a falling object when the only force acting on it is gravity
Freefall
What causes an object in freefall to accelerate
The force of gravity is an unbalanced force which uses an object accelerate
Near the surface of earth the acceleration due to gravity is.
This means that for every second an object is falling it’s velocity increases by 9.8 m/s
9.8 m/s
The fluid friction of Upward force of air on the downward motion of an object
Air resistance
When the force of air resistance upward equals the weight of the falling object (gravity force) the object stops doesn’t accelerate, falls at constant speed
Terminal velocity
The motion of an object when thrown horizontally on earth
Projectile motion
What is the shape of projectile motion
A curved path because a resistance and gravity are both acting simultaneously
Claims that an object at rest will stay at rest and an object exerts a force on another object then the second object exerts a force of equal strength in the opposite direction on the first object
Newton’s first law
Tendency of an object to resist any change in its motion
Also called newtons 1st law
Inertia
How is mass related to inertia
The greater the mass the greater its inertia
Acceleration: depends upon and objects mass and the net force acting on the object
Newtons 2nd law
Acceleration is measured in
M/s2
Mass is measured in
Kg
Forces math formula is
Mass x acceleration
Force is measured in
Newtons
If one object exerts a force on another then the second object exerts a force of equal strength in the opposite direction on the first object
for every action there is an equal but opposite reaction force
Newtons third law
How can action reaction forces not cancel each other out
When the forces act on different objects
How can momentum be determined
The momentum of a moving object can be determined by multiplying the objects mass and velocity
What is the correct unit for momentum
Kg x m/s
The rule of fact in the absence of outside forces the total momentum of object that interact does not change
A common outside force is friction
Law of conservation of momentum
How does a rocket lift off the ground
Gasses the rocket expels with a downward action force. The action force causes the rocket to lift upward with an equal reaction force. As long as this upper pushing force called thrust is greater than downward pull of gravity there is a net force in upward direction. As a result the rocket accelerates upward into space
What is the satellite
Any object that orbit another object in space
If force that causes an object to move in a circular path
Centripetal force
What is the centripetal force of the satellite
The gravitational force pulls satellites towards the center of Earth
Describe the path of a projectile motion
Curved path
The object moves forward while gravity pulls it downward
