P5 - forces Flashcards
is force a vector or a scalar?
vector
what’s the difference between a vector and a scalar?
vectors have a magnitude and a direction, scalars only have a direction
name 5 vector quantities
force, velocity, displacement, acceleration, momentum, etc.
name five scalar quantities?
speed, distance, mass, temperature, time
what are vectors usually represented by?
an arrow - the length of the arrow shows the magnitude, and the direction of the arrow shows the direction of the quantity
what is the equation for weight? what are the units for all of the measurements?
weight(N) = mass (kg) x gravitational field strength (N/kg)
what is the relationship between weight and mass?
they are directly proportional
when a chair is sat on the ground, what is the force of the ground on the chair called?
normal contact force
what is an interaction pair?
a pair of forces that are equal and opposite and act on two interacting objects (basically Newtons third law)
name 4 contact forces:
friction, air resistance, tension in ropes, normal contact force
what is a force?
a push or pull on an object that is caused by it interacting with something
what are the two types of forces
contact or non-contact
what is a contact force?
when two objects have to be touching for a force to act
what is a non-contact force?
a force where the objects do not need to be touching for the force to act
name three non-contact forces
magnetic force, gravitational force, electrostatic force
what is gravitational force?
the force of attraction between masses
what is weight?
the force acting on an object due to gravity (the pull of the gravitational force on the object)
what is force measured in?
newtons
where does a force act from on an object?
a single point, called it’s centre of mass (a point at which you assume the whole mass is concentrated)`
what is a uniform object?
one that’s that same density throughout and is a regular shape
where will the centre of mass be on a uniform object?
at the centre of the object
what is weight measured with?
a calibrated spring balance (or newtonmeter)
is mass a force?
no
what is mass measured in?
kilograms