Forces
Force is a ______ or _______ motion
A push or pull
Describe balanced forces
Forces that are equal in magnitude and opposite in direction
What are contact forces?
Forces that occur between objects that are touching.
Using a lever, the longer the effort arm the (more or less?) force is needed to lift a weight
Less for is needed the longer the effort arm
What is gravity? Describe.
Gravity is a force of attraction between all objects. The strength of the force depends on the mass of the objects and the distance between objects.
List 3 things a force can do to an object
Speed an object up
Slow an object down
Stop an object that was moving
Start an object that wasn't moving
Turn an object
Change an object's shape
What are unbalanced forces?
Forces that act on an object that are not equal in magnitude and opposite in direction.
What are non-contact forces?
Forces that occur between objects that are not touching each other.
The further an object is placed on the resistance arm the (faster or slower?) it moved when effort is applied
An object moves faster when places further along the resistance arm
Do all objects on Earth have a gravitational attraction between them?
yes
Define Vertical and Horizontal
Verticle is up and down
Horizontal is side to side
Describe 2 objects with balanced forces acting on them.
Any still or constantly moving object e.g.Computer on desk. Apple on tree
List 3 contact forces
Applied
Normal
Tension
Air resistance
Friction
What is the pivot or balancing point of a lever called
Fulcrum
What 2 things impact the strength of a gravitational field (or the force of gravity)?
Mass --> larger = more force
Distance --> closer = more force
The man responsible for the Laws of Motion
Isaac Newton
What happens to an object when unbalanced forces are acting on it?
It changes speed, direction or shape
List 2 non-contact forces
Gravity and magnetism
When the resistance arm is increased the lever acts as a _______ multiplier
Speed multiplier
Describe the difference between mass and weight.
Mass is a measure of the amount of matter in an object.
Weight is a measure of the amount of matter in an object and how much gravitation force is being applied to the matter.
What 2 things do force arrows tell you about a force?
Strength (magnitude) of the force and direction the force is acting.
If a skydiver is moving at a constant speed, are the forces on them balanced or unbalanced? Explain.
The forces are balanced if the object is moving at a constant speed, because unbalanced forces results in a change in motion of objects or a change in shape.
Explain why air resistance is a contact force
Air resistance is a contact force because air particles are in contact (directly touching) an object that is falling, and create friction between the falling object and the air particles.
When the effort arm is increased the lever acts as a ________ multiplier
Force Multiplier
The International Space Station orbits at an altitude of 370 km where the Earth's gravitational field strength is 8.8 N/kg.
Calculate the weight of an 90 kg astronaut "floating" in the space station.
Include the correct units in the answer.
792N