forces - acceleration Flashcards
what does the acceleration of an object tell us?
the change in its velocity over a given time
acceleration equation?
acceleration (m/s squared) = change in velocity (m/s) / time (s)
change in velocity = final velocity - initial velocity
what does it mean if you get a negative number from acceleration equation?
the object is slowing down, deceleration
how to calculate acceleration on a velocity time graph?
the gradient if velocity time graph tells us the acceleration of the object
On a velocity time graph, a horizontal line =
an upward sloping line=
a downward sloping line=
a)object travelling at a constant velocity
b) accelerating
c) decelerating
what does the total area under the velocity time graph tells us?
the distance travelled in a specific direction
what do we do to work out distance/displacement when we see constant acceleration and constant deceleration?
divide graph into shows and calculate their total area
how do we calculate distance/displacement when acceleration and deceleration is not constant?
we count squares under the graph. count complete squares and then estimate total of other squares. then find area of square and multiply by how many there are.
how to work out acceleration if object is moving at a constant rate?
v squared - u squared = 2as
final velocity (m/s) - initial velocity (m/s) = acceleration (m/s squared) x distance (m)
when any object falls towards the surface of the earth, what is the initial acceleration? what is this due to?
around 9.8 m/s squared
b) due to the force of gravity acting on the object
what does skydiver experience as he falls?
an upward force of friction with the air particles - air resistance. after some time the force of air resistance balances the force due to gravity. at this point, object stops accelerating and experiences a constant velocity which is called terminal velocity. applies to any object falling through fluid eg air
what does terminal velocity depend on? why do some objects experience a greater force of friction?
a) depends on object
b) due to their shape so they will have a lower terminal velocity
