Forces Flashcards
what is a scalar quantity?
it has magnitude(size) only e.g the number of apples
what is a vector quantity?
it has magnitude(size) and direction e.g velocity.
what is the velocity of something?
it shows the speed and the direction of travel
in vector quantities what can the length of an arrow represent?
it shows the magnitude
in vector quantities what can the direction of the arrow represent?
the arrow points in the direction that the vector quantity is acting
what is an example of a vector quantity?
forces
when does a force occur?
when two or more objects interact
forces are either…
contact or non- contact forces
what is a contact force?
when the objects are actually touching.
what are examples of contact forces?
friction, air-resistance/drag, tension, normal contact force, upthrust
what is a non-contact force?
when the two objects are not touching.
what are examples of non-contact forces?
gravitational force, electrostatic force, magnetic force
what is friction?
The resistance that one surface or object encounters when moving over or through another material. Friction generally causes heat.
what is air- resistance/drag?
the force acting on an object that is moving through air flowing in the opposite direction. The air “resists” the object’s movement, slowing it down by friction that is created as the object collides with air molecules.
what is tension?
the pulling force that a string or cable exerts (creates) when something or someone pulls on it.
what is upthrust?
a force that pushes up on an object submerged in a fluid It is always in the opposite direction to the object’s weight.
what is gravitational force?
objects have a force pulling them down due to their mass. The gravitational field is responsible for the force of gravity close to Earth. Around the earth, there is a gravitational field which pulls objects down.
what is electrostatic force?
Two objects with the same type of charge will repel, whilst two oppositely charged objects attract. The force between unlike charges is called electrostatic attraction.
what is magnetic force?
an attraction or repulsion that arises between electrically charged particles because of their motion.
what is gravity ?
a force of attraction between all masses.
what is the force of gravity close to the earth due to?
the gravitational field around the planet
what is the mass of an object?
it relates to the amount of matter it contains and is constant
what is the force acting upon an object due to gravity?
weight.
what does the weight of an object depend on?
the gravitational field strength, where the object is and its always directly proportional to its mass.
the weight of an object is always directly proportional to what?
its mass
what is a resultant force ?
when more than one force acts on an object, these forces can be seen as a single force that has the same effect as all the forces acting together.
what are scale vector diagrams used to illustrate?
the overall effect when more than one force acts upon an object, the forces are added together to find a single resultant force, including magnitude and direction. the vectors are added head to tail and a resultant force arrow is drawn.
when can scalar vector diagrams also be used?
when a force is acting in a diagonal direction, expressing the diagonal force as two forces at right angles to each other can help work out what effect the force will have
what can force Fr be broken down into?
F1 and F2, F1 is the same length as the length of Fr in the horizontal direction and F2 is the same length as Fr in the vertical direction.
how do you find Fr?
Fr = F1+F2
what are the measurements of the aspects in the equation: Weight = mass x gravitational field strength?
weight is measured in newtons
mass is measured in kg
gravitational field strength is measured in newtons per kg
what happens when a force causes an object to move? why?
work is done on the object, because it requires energy to move the object.
1 joule = __ newton metres?
1 newton metre, one joule of work is done when a force of one newton causes a displacement of one metre.
what is the definition of displacement?
the change in position or placement of an object