definitions Flashcards
distance
how far an object has moved (scalar)
displacement
the amount by which a thing has moved from it’s original position (vector)
equation for average speed
speed = distance
—
time
vector
a quantity that has a both a magnitude and a direction
scalar
a quantity that only has a magnitude
scalars?
distance, mass, speed, energy
vectors?
force, displacement, momentum, acceleration, weight, velocity
what is the difference between speed and velocity?
speed: scalar, only magnitude (size)
velocity: vector, magnitude(size) + direction
centripetal force
a force that acts on a object moving in a circular path and is directed towards the center around which the object is moving
newton’s first law
an object does not need a resultant force to keep moving - it only needs a resultant force to speed up, slow down or change direction
mass
a quantity of matter in an object
weight
the pull force the object experiences depending on the gravitational field strength
normal force
an opposing force from the ground acts upwards
force
something that acts on an object that can change its shape, direction or speed
average walking speed?
1.4 m/s
average running speed?
3 m/s
average cycling speed?
6 m/s
average speed of car in a town?
13 m/s
average speed of car on a motorway?
30m/s
average rain speed?
50 m/s
average aeroplane speed?
250 m/s
average wind speed?
3 - 20 m/s
average sound speed?
340 m/s
average lorry speed?
25 m/s
two things used to measure speed in a experiment?
- stopwatch
- light gates
equation for acceleration?
a = (v - u)
—
t
what does gradient represent on a distance/time graph?
velocity
what does horizontal line represent on a distance/time graph?
that the object’s stationary
what does curve represent on a distance/time graph?
that the object is accelerating or decelerating
what does straight slope represent on a velocity/time graph?
acceleration
what does horizontal line represent on a velocity/time graph?
that the object is at a constant velocity
what does curve represent on a velocity/time graph?
a changing velocity
value of acceleration due to gravity -
10 m/s squared
summary of newton’s first law
a moving object will remain at a constant velocity until an external force acts on it
a stationary object will remain stationary until an external force acts on it
what will a non-zero resultant force produce?
it will always production acceleration (or deceleration) in the direction of the force
the car is changing direction so it is accelerating. why?
acceleration is a vector force, if the direction changes the force changes so it is constantly accelerating
