Velocity
What are the standard units of velocity in physics?
meters per second (m/s)
what are the standard units of acceleration in physics?
m/s/s or m/s2
what does the letter "g" stand for?
acceleration due to earth's gravity
What do we call the point in space that we use to compare an object's position to?
reference point
a car drives 10 meters backward in 2 seconds. What is the velocity of this car?
-5 m/s
A racecar accelerates at a rate of 7 m/s2 for 4.5 seconds until it reaches a velocity of 85 m/s. What was the initial velocity of this racecar?
53.5 m/s
What is the equation for velocity and what does each symbol stand for?
v = d / t (velocity = displacement / time)
What is the equation for acceleration and what does each symbol stand for?
a = (vf - vi) / t
At what rate do falling objects accelerate?
9.8 m/s2
displacement is defined as a change in an object's __________.
position
A ball is tossed upward and moves 35 meters in 5 seconds. What is the velocity of this ball?
7 m/s
John runs 10 meters east. Stacy runs 10 meters west. Which statement is true?
a. They have the same velocity but different speeds
b. they have the same speed but different velocities
c. they both have the same speed and same velocity
d. they have different speeds and different velocities
b. Different velocities because they are moving in different directions
What are all the possible ways an object can accelerate?
speed up, slow down, turn / change direction
What does it mean for an object to be in "freefall"?
Gravity is the only force acting on the object.
velocity is defined as _________________.
The RATE of change in an object's position.
A train speeds up from 20 m/s to 65 m/s in 9 seconds. What is the acceleration of this train?
5 m/s2
What TWO things do you need to know about an object to accurately describe its velocity?
Its speed and direction.
Which of the following objects is NOT accelerating?
a. A car slows down on the freeway
b. A SpaceX rocket launches upward
c. You move at a constant speed of 25 m/s around a Ferris wheel
d. You jog at a constant velocity of 5 m/s east
d. All the rest are accelerating because they change speed OR direction!
Which of the following objects are NOT in freefall?
a. rock falling off of one story building
b. piece of paper falling off desk
c. moon orbiting earth
d. rocket while coming in for a landing
b and d (there objects are experiencing other forces aside from gravity)
Acceleration is defined as ____________.
The rate of change in an object's velocity.
A ball tossed upward slows from 30 m/s to 12 m/s in 3 seconds. What is the acceleration of this ball?
-6 m/s2
Which three directions are generally defined as the negative directions in physics?
backward, leftward, and downward
An airplane moving at 100 m/s has an acceleration of -8 m/s2. How fast is the plane moving after 3 seconds?
76 m/s
A baseball, a small marble, and a bowling ball fall from a height of 10 feet. Which of these objects will have the GREATEST acceleration?
all the same! 9.8 m/s2
Which of the following quantities are NOT a vector:
a. displacement
b. velocity
c. acceleration
d. gravitational acceleration
e. time
e. Time is a quantity that does not have direction.
A ball is dropped from a bridge and hits the ground, coming to a stop. The velocity of the ball just before hitting the ground is 67 m/s. How long was the ball falling (time)? **Round to one place after the decimal.
6.8s