Forces Flashcards
What is a force?
A push or pull on an object due to its interaction with another object?
What is the unit used to measure force?
Newton (N)
What instrument do we use to measure a force?
Spring balance
Can force be measured?
Yes, a force is a physical quantity.
What physical quantities does a force have?
Size and direction.
What are these types of physical quantities (size and direction) called?
Vectors
How can vectors be represented?
By an arrow which is drawn to scale.
What does the length of the arrow represent?
The size
What does the arrowhead tell us?
The direction.
How else can direction be given?
Cardinal points or as bearing.
What are the effects of force?
Alter the motion of an object (moving to stationary/stationery to moving)
Change direction of a moving object.
Change shape of object by exerting a force.
Change the speed of an already moving object.
When is the net force great than 0N?
When forces are acting in opposite directions, but aren’t equal.
What are the two types of forces?
Contact and non-contact forces.
What is a contact force?
A force that results when two objects are physically touching each other.
What is a non-contact force?
A force that can act over a distance. This means that the two objects have an effect on one another even when they are not touching each other.
What is friction force?
Simple: a force that opposes motion.
The resistance that one surface or object experience when moving over another surface or object, or through a substance (liquid or gas).
Which direction do friction forces always act in?
The opposite direction to the motion of the object.
What does the size of frictional forge depend on?
The type of surface on which an object is moving (the smoother the surface the less friction there is)
The normal surface (acts in opposite direction to the weight of object)
What is the normal force?
It’s a contact force that prevents you from penetrating the ground. It always acts perpendicularly to the surface that the object is resting on.
What are the advantages of friction forces?
Friction between our feet and the ground enables us to move forward without slipping.
Friction between the tread at a rude and the road prevents cars from slipping.
What is a tension force?
Two forces acting on one object in opposite directions (away from each other) to stretch the object/pull it apart.
What is a compression force?
Two forces acting on one object in opposite directions (towards each other) to compress or deform the object.
What is muscular force (applied force)?
Force applied by a person or an engine on an object.
Must involve a person or engine.
What is gravitational force?
A force of attraction (pulling force) between two objects/bodies over a distance due to their masses.
What does the size of the gravitational force depend on?
The greater the mass of the objects, the stronger the gravitational force of attraction between them.
The closer the objects are to each other, the strong the gravitational force between them.
Name three differences between mass and weight.
Mass: the amount of matter an object consists of.
Weight: gravitational force exerted on the object by the earth (or any other planet).
Mass: measured in kg.
Weight: measured in N
Mass: remains the same whenever it’s measured.
Weight: can change depending on where it is measured.
What is the formula to work out the weight?
Mass x gravitational acceleration
What type of force is a magnetic force?
Non-contact
Which poles attract?
Unlike poles
Which poles repel?
Like poles
Which direction do the arrows always go in a magnet?
From North to South. (Towards south)
In at south, out at north.
When does the strength of a magnetic field weaken?
As you get further away from the magnet.
How is electric charge transferred from one object to another in electrostatic forces?
Friction
What happens when an object loses electrons?
It will have more protons than electrons and will therefore be positively charged.
What happens when an object gains electrons?
It will have more electrons than protons, therefore making it negatively charged.
What is an example of a huge electrostatic discharge?
Lightning.
What is the gravitational acceleration on Earth?
9.8m/s
What is the gravitational acceleration on the moon?
1.6m/s
What is an electrostatic force?
A force that electrically charged objects to exert on each other over a distance.
What is electrostatic force?
A force that two electrically charged objects exert on each other over a distance.
