Describing Motion
The SI unit of distance:
meter
How do you calculate an object's instantaneous speed
Speed = Distance / Time
The units for acceleration
meters per second squared (m/s2)
A stone is dropped into a deep well and is heard to hit the water 2.15 s after being dropped. Determine the depth of the well.
d = 22.67 m
True or False: A planet orbiting the sun at a constant speed is accelerating
True, a change in direction is also acceleration
The only way to tell if an object is moving is to use this:
Reference point
What is the difference between speed and velocity?
Velocity is speed in a given direction
What change must be seen in an object to qualify as acceleration?
Change in speed or direction
A kangaroo is capable of jumping to a height of 2.62 m. Determine the takeoff speed of the kangaroo.
vi = 7.17 m/s
True or False: Two objects traveling at the same speed have different velocities if they are traveling in the same direction
When flying in an airplane, name one thing that is stationary relative to you
Seats, wings, passengers, etc.
Average speed
Negative acceleration
A dragster accelerates to a speed of 112 m/s over a distance of 398 m. Determine the acceleration (assume uniform) of the dragster.
a = 15.8 m/s2
A distance over time graph for a runner shows a constant positive slope. What can the runner do to increase the slope of the line?
Increase his speed
A graph of distance over time shows a slope of 0. What does this mean in terms of the objects motion?
The object is not moving
The slope of a speed versus time graph represents this:
Acceleration
The gravitational acceleration constant of Earth:
a = 9.81 m/s2
If Michael Jordan has a vertical leap of 1.29 m, then what is his takeoff speed and his hang time (total time to move upwards to the peak and then return to the ground)?
vi = 5.03 m/s and hang time = 1.03 s
The German scientist responsible for theorizing that time slows down the faster you move towards the speed of light
Einstein
A distance over time graph shows a nonlinear exponential relationship. What does this mean in terms of the object's motion?
The object is accelerating.
Nick rides on a carousel and tosses a ball up and down. Nick observes the motion of the ball moving straight up and down. What is the apparent motion of the ball relative to someone sitting next to Nick on the carousel?
He observes the same as Nick, the ball moves straight up and down
Name one kinematics equation that relates distance to time and acceleration
d = Vit + 1/2at2
A plane has a takeoff speed of 88.3 m/s and requires 1365 m to reach that speed. Determine the acceleration of the plane and the time required to reach this speed.
a = 2.86 m/s2 and t = 30. 8 s
The variable used to represent the speed of light
c