Force and motion Flashcards
Acceleration
Is the rate of change of velocity per unit time (vector quantity
Displacement
the change in position of an object (vector quantity
Distance
the total length of a given path between two points (scalar quantity)
scalar quantity
Is a quantity that has only magnitude (size)
Speed
the rate of change of distance per unit time (scalar quantity
Vector quantity
a quantity that has magnitude (size) and direction
Velocity
the rate of change of displacement per unit time (vector quantity
Velocity conversions. ms –> kmh
To convert from m s-1 to km h-1, multiply by 3.6. To convert from km h-1 to m s,-1 divide by 3.6.
Average velocity formula
v = Δs/ Δt = s2 − s1/ t2 − t1
v = average velocity (m s−1), s = displacement (m), t = time (s)
Instantaneous velocity
Instantaneous velocity describes the velocity at an instant in time. The instantaneous velocity can be calculated using the formula for average velocity if the velocity is constant. Instantaneous speed is always equal to the magnitude of the instantaneous velocity.
Acceleration formula
a = Δv /Δt = v − u/ t2 − t1
a = acceleration (ms-2), v = final velocity (ms-1), u = initial velocity (ms-1), t = time (s)
Constant acceleration equations
Equilibrium
the state of having all the forces acting on an object in balance which means the net force on the object is zero
Force
a push or a pull with an associated magnitude and direction (vector quantity)
gravitational force
the force experienced by an object due to the gravitational field of another object
net force
the vector sum of all forces acting on an object
Newton’s first law
law that states an object will accelerate only if a non-zero net force (unbalanced force) acts upon it
Newton’s second law
law that states the acceleration of an object is equal to the net force applied divided by the mass of the object being accelerated
Connected bodies
Two or more objects in direct contact or attached such as through a rope of cable.
Newton’s third law
law that states that for every force there is a reaction force of equal magnitude and opposite direction
normal force
the contact force that acts between two objects with the equal magnitude on each object and at right angles to the contact surfaces
Friction
a force that resists the relative motion of two surfaces which are in contact