motion
what two things must you need to calculate speed?
total distance
total time
what is the SI unit of force?
Newton (N)
what type of force opposes motion, causing moving objects to slow down and/or stop?
friction
what is gravity?
force of attraction between objects
what is the difference between speed and velocity?
velocity has a direction.
speed is distance traveled over time.
what is a force?
a push or pull
describe two ways friction can be reduced.
1. apply lubricant
2.smooth surface
what two things affect gravity?
1. mass
2. distance
Emily can skateboard 120 meters in 8 seconds what is her average speed?
15 m/s
clay and Tyler were helping a friend move a couch. clay pushed couch with 25 N east Tyler pushed with 15 N east. clay's little sister pushed back at 10 N west. Calculate the net force.
30 N east
the force of friction exerted by a surface depends on:
the smoothness of the surface
what is the one law of universal gravitation
1.larger mass =more gravity
2. greater distance=less gravity
why is it more helpful to know a tornado's velocity rather than its speed
velocity tells direction, allowing people to get out of danger and move in a safe direction
what may happen when an object receives unbalanced forces?
it may move
there is a wagon shown what two forces are acting on it
normal force gravity force
whats the SI unit for mass?
kilogram (kg)
a kangaroo hops 60 meters to the east in 5 seconds. what is the kangaroos velocity?
12 m/s
describes three different ways you can accelerate when riding your bike.
1. slow down
2. speed up
3.change direction
a woman is pushing a stroller what force is shown?
applied force
describe two differences between weight and mass.
1. weight is force of gravity on an object
2. mass never changes.