Forces 1 Flashcards
What is a force?
a force is a push or pull on an object caused by it interacting with another object
What can (unbalanced) forces do?
when an object experiences a force, it can:
- deform (change shape)
- change speed (move: acceleration, deceleration)
Contact or non-contact?
friction
contact
Contact or non-contact?
push/pull
contact
Contact or non-contact?
drag (water/air resistance)
contact
Contact or non-contact?
lift (force on wings that keep it up)
contact
Contact or non-contact?
upthrust (upward force exerted on object in liquid)
contact
Contact or non-contact?
normal contact force (force exerted on an object through contact with a solid)
contact
Contact or non-contact?
weight
non-contact
Contact or non-contact?
magnetism
non-contact
Contact or non-contact?
electrostatic
non-contact
Contact or non-contact?
tension (force in a string holding up a picture)
contact
Contact or non-contact?
thrust (propulsive force from an engine)
contact
What is weight?
weight is the force acting on an object due to gravity
What is weight measured in?
Newtons (N)
What is mass measured in?
kilograms (kg)
What is gravitational field strength measured in?
Newtons per kilogram (N/kg)
What is the formula for weight?
weight = mass x gravitational field strength (W=mg)
What is the formula for mass?
mass = weight / gravitational field strength (m=W/g)
What is the formula for gravitational field strength?
gravitational field strength = weight / mass (g=W/m)
Can mass change?
no
Can weight change?
yes
What is upthrust?
The upward force exerted on an object that is in or on a fluid
What is friction?
The force that opposes movement of an object sliding over a surface
What is tension?
The force in a string holding up a picture
What is lift?
the force on the wings of an aircraft that keeps it flying
What is normal contact force?
the force that a solid surface exerts against an object
What is drag?
the force that acts against an object moving through fluid.
What is thrust?
the propulsive force from an engine
What is electrostatic?
the force between charged particles
What is magnetic?
The force between a magnet and an iron nail
Elastically deformed
An object has been elastically deformed if it can go back to its original shape and length when the force is removed.
Inelastically deformed
An object has been inelastically deformed if it doesn’t return to its original shape and length when the force is removed.
What is Hooke’s law?
The extension of an object that obeys Hooke’s law is directly proportionate to the force applied. Any % change in one variable leads to a % change in the other variable.
What is the formula for Hooke’s law?
Force = spring constant x extension (F=ke)
What is force measured in?
Newtons (N)
What is the spring constant measured in?
Newtons per metre (N/m)
What is the extension measured in?
metres (m)
When is Hooke’s law applicable?
Hooke’s law is only applicable up to the limit of proportionality.
What does “∝” mean?
directly proportional
What is the “spring constant”?
the spring constant is the measure of the “stiffness” of the spring (how easy it is to stretch)
