Math
The average speed of a runner who runs 400 m in 96 s is ________.
Speed=distance/time
4.2 m/s
An object that changes position relative to a reference point is
in motion.
On a distance vs. time graph of an object's motion, distance is usually:
the dependent variable.
24 s represents
time (seconds)
When velocity changes by the same amount over each time interval, acceleration is
constant
A car moving at an average speed of 44 mi/h for 4.25 h has traveled...
distance = velocity X time
187 miles
The __________ of an object consists of its speed and direction.
velocity
When the motion of an object is shown by a straight line on a distance vs. time graph with distance on the y-axis, the slope of the line is the
speed
Average speed can be represented by the mathematical expression
Speed= distance / time
What happens when a car slows down and velocity changes?
negative acceleration
A pitcher throws a baseball toward home plate, a distance of 60.5 ft. The ball reaches home plate in 0.63 s. What is the velocity of the ball?
Velocity (speed) = distance / time
96 ft/s toward home plate
Displacement must always indicate
direction
Peter runs in a constant direction on a straight road. The velocity vs. time graph of Peter's motion shows a straight line with a negative slope. What does the line tell you about Peter's speed?
It is decreasing.
15 m represents
distance
Change in speed with direction
On a bus traveling north at 20.0 m/s, a child stands up and walks toward the back of the bus at 1.3 m/s. What is the child's resultant velocity?
18.7 m/s north
Speeding up, slowing down, and changing direction is best described as
acceleration
On a distance vs. time graph, the line of an object at rest is a
flat line (horizontal)
Net force is
the combination of all the forces acting on an object.
An object experiencing balanced forces
has a net force of zero
Moving from 0 m/s to 25 m/s in 8.0 s equals an average acceleration of...
Acceleration = (final velocity - initial velocity) / time
3.1 m/s²
When centripetal acceleration occurs, an object
changes direction
On a velocity vs. time graph, what shows the value of the acceleration?
the slope of the line
The equation for finding average acceleration for straight-line motion is
acceleration=(final velocity – initial velocity) / time.
A game of tug-of-war is an example of
unbalanced forces