Science Force Flashcards
Force
A push or a pull
Net force
the combination of all forces acting on a object
Force is described by
Its strength and by the direction in which it acts
SI units for force
Newtons
Formula for force
F= M x A
1N = ___ kg x ____ m/s/s
????
What do scientist use to represent a force?
F or an arrow
The device you used to measure force with your shoe
Spring scale
What are balanced forces?
Give example
When two equal forces act in opposite directions to cancel each other out.
Two people pushing on a box across from each other and the box does not move
What are unbalanced forces?
Give example
Forces acting on an object result in a change in motion
You and Laura pushing against each other on a box
Newton’s 3 Laws of Motion
- Object at rest will remain at rest. Object in motion will stay in motion
- Acceleration depends on the objects mass and on the net force acting on the object (A= F/M)
- For every action there is an equal and opposite reaction
Inertia
tendency to resist change in motion
SI units for mass
kg
SI units for velocity
m/s
Calculate Acceleration
A = F / M
How can you change the acceleration of an object?
Change the force used to move it. (Push or pull harder or lighter)
Friction
Force that two surfaces exert on each other when they rub against each other
Rolling friction definition
give an example
when an object rolls across a surface
skateboard, bike, tires
Sliding Friction Definition
give example
When two solids surfaces slide over each other.
Sand on ice to keep from falling, brake pad on tires, your skin on concrete when you crash bike
Fluid friction definition
Give example
Occurs when solid moves through a liquid.
Surf board, water ski, bike helmet with air
Static Friction
Give example
Friction that acts on objects that are not moving.
Pushing heavy desk that wont move
Four types of friction
- Fluid
- Rolling
- Sliding
- Static
Weight
Force of gravity on a person or object at the surface of a planet
Mass
measure of the amount of matter in an object
Acceleration due to gravity
9.8 m / s*s
Terminal velocity
the greatest velocity a falling object reaches
Air resistance
Fluid friction that objects experience falling through the air.
Remember that air resistance is an upward force on an object falling down
Free fall
When the only force on an object is gravity
Law of Universal Gravitation
The force of gravity acts between all objects in the universe. Gravity acts everywhere not just on Earth.
Convert a weight into Newtons
1 lb = .45kg (1N=.224lbs)
Formula for momentum
Momentum = mass x velocity
Law of Conservation of Momentum
In the absence of outside forces - the total momentum of objects that interact does not change.
The amount of momentum is the same before and after they interact
Example of outside force
Friction
Which of Newton’s Laws explains how a rocket lifts off?
Gas force exerts an equal but opposite reaction force on the rocket (Newtowns 3rd law)
What is a satellite
Any object that orbits another object in space
Name a natural satellite
asteroid
Three purposes of artificial satellites
- Communication
- Weather analysis
- GPS
Name the artificial satellite for scientific research?
International Space Station
What two forces act on satellites?
- Centripetal force
2. Gravitational force
When an unbalanced force acts on an object the force
changes the motion of the object
Air resistance is what type of friction?
Fluid friction
Which of the following is not a projectile?
satellite, thrown ball, ball on the ground, soaring arrow
ball on the ground
The resistance of an object to any change in its motion is called
inertia
The product of an objects mass and its velocity is called the object’s
momentum
T/F
Balanced forces are equal forces acting on an object in opposite directions
True
T/F
Rolling friction occurs when two solid surfaces slide over each other
True
T/F
The greatest velocity a falling object reaches is called its momentum
False
Its Terminal Velocity
T/F
The law of universal gravitation states that the total momentum of objects that interact does not change
Universal law of momentum
T/F
The type of force that causes a satellite to orbit earth is a centripetal force
True
Type Occurs Example of Friction When static sliding rolling fluid
static object not moving pushing heavydesk
sliding two against other skin wrecking bike
rolling one rolls against other skateboard
fluid solid thru liquid bike helmet air or ski
