Describing Motion
Speed equals distance divided by ____
Time
when you know both the speed and direction of an object's motion, you know the ____
velocity
a push or pull applied to an object
friction
the tendency of an object to resist change in its motion
inertia
any two masses that exert an attractive force on each other
gravity
The total distance traveled divided by total time
What is average speed
To determine the acceleration rate of an object, you must calculate the change in speed during each unit of _______
time
the force that one surface exerts on another when the two surfaces rub against each other is called ____
friction
the achievement of lifting a rocket off the ground and into space can be explained by ____
Newton's 3rd Law
The unit for gravitational force exerted on an object
Newton
If you know the distance an object has traveled in a certain amount of time, you can determine ____
the speed of the object
If speed is measured in kilometers per hour and time is measured in hours, the unit of acceleration is ___
km per hr per hr
balanced forces acting on an object ____
never change the object's motion
According to Newton's 2nd law of motion, _____ depends on an object's mass and the net force acting on the object
acceleration
any force that causes an object to move in a circle is called a
centripetal force
If a bicyclist travels 30 kilometers in two hours, her average speed is ____
15 km/hr
In an acceleration graph showing speed vs time, a straight line shows the acceleration is ____
constant
bike tires on the road as you ride, is an example of ___
rolling friction
for every action there is an equal but opposite reaction
3rd law
an object that is thrown
projectile
the rate at which an object is moving at a given instant
What is instantaneous speed
Acceleration is the rate of change in ____
velocity
what happens when two forces act in the same direction
they add together
A person traveling in a car that stops suddenly keeps moving forward due to ______
inertia
means towards the center
centripetal