motion & forces Flashcards
(44 cards)
what’s the difference between distance and displacement
distance = how far an object moves, scalar quantity displacement = the distance an object moves in a straight line from the starting point to the finishing point, vector quantity
is velocity scalar or vector
vector - has both magnitude and direction
name some scalar quantities
mass, energy, temperature, speed, distance
name some vector quantities
force, velocity, acceleration, momentum, displacement
if a car travelling at +10m/s suddenly turns around and continues at the same speed, what is its new velocity
-10m/s
what is momentum
a combination of mass and velocity, it is a vector quantity
how do you calculate speed
speed = distance / time taken
how do you calculate speed from a distance/time graph
speed = gradient of the line
distance/time taken
on a speed/time graph, what does the gradient mean
acceleration
how do you find the distance travelled from a velocity/time graph
the area under the line
what are light gates used for
to see how long it takes an object to pass through them, you calculate the speed using v = x / t
(x is the length of the object)
what is the equation for acceleration
acceleration (m/s^2) = change in velocity / time taken
a = v^2 - u^2 / t
what’s the equation for final speed
initial speed + (acceleration x time)
how do you calculate final velocity
v^2 - u^2 = 2ax
x = distance
if an object decelerates, how would you write the acceleration of it
a negative number m/s^2
what is the acceleration due to gravity
9.8 m/s^2
how could there be a change in velocity but not a change in speed
if an object is travelling at a constant speed but is also changing direction
what is a resultant force
the sum of all forces acting on an object, if the forces acting on an object are unbalanced then there is a resultant force acting on the object
it will always act towards the centre of the circle if moving in a circular motion
what is the equation for resultant force
resultant force = forces acting in one direction - forces acting in the opposite direction
what is newton’s first law
that the velocity of an object will only change if a resultant force is acting on the object
what is newton’s third law
when 2 objects interact, the forces they exert on each other are equal and opposite
how do you calculate force
mass x acceleration
how do you calculate momentum
mass x velocity
what is the law of conservation of momentum
momentum cannot be created or destroyed
