Acceleration Problems
An moving object with a curved position vs time graph indicates?
The object's velocity is changing and the object is accelerating.
What is the sign for free-fall acceleration on Earth?
Negative
How can you calculate the displacement of an object from a graph of it's velocity vs. time?
Area between the line and the x axis
What does the sign of the velocity, acceleration, or displacement signify?
direction
What is the variable used to describe the acceleration due to gravity on the earth? What is it's numerical value?
g; -9.8 m/s^2
How long does it take an object to accelerate from 5 m/s east to 45 m/s east with an acceleration of 7 m/s2 east? Round to nearest whole number.
6 seconds
A cannon ball is shot into the air. On its way down back to earth, its velocity is ____&____ and its acceleration is ____&____.
negative & increasing; negative & constant
What is the rule for progression of graphs from position vs time, to velocity vs. time, and to acceleration vs. time?
Curve, diagonal, horizontal, zero
If the sign of v is positive and the sign of a is positive, what direction is the object traveling and is it speeding up or slowing down?
Positive direction; speeding up
What is the definition of acceleration?
Change in velocity
A carnival ride is traveling forward at a velocity of 10 m/s. The carnival ride is accelerating at 2 m/s2 backward. After 6 seconds, what is the velocity of the carnival ride?
2 m/s backward
A pitcher throws a ball vertically upward at a velocity of 15 m/s. When the ball returns to his mitt, what velocity is the ball travelling?
-15 m/s
What is the object's displacement if it accelerates from rest to a velocity of 60 m/s in 10 seconds?
300 m
If the sign of v is negative and the sign of a is negative, what direction is the object traveling and is it speeding up or slowing down?
Negative direction; speeding up
What force(s) act on a body in free-fall?
only the force of gravity
An object accelerates at a constant rate of 3 m/s2 for a time period of 10 seconds. What is the change in velocity of the object?
30 m/s2
It takes a student 18 cm to react to a dropped ruler. What is the student's reaction time?
0.19 sec
The area under an acceleration vs time line graph is the _________.
The change in velocity.
If the sign of v is positive and the sign of a is negative, what direction is the object traveling and is it speeding up or slowing down?
Positive direction; slowing down
What are the three ways an object can accelerate?
Speed up, slow down, or change direction.
A car accelerates from rest to a speed of 20 m/s in 15 seconds. During the same time, a bus accelerates from a speed of 30 m/s to 40 m/s. Which vehicle had the greater acceleration?
The car
A marker falls from a student's desk that is 0.95 m high. What is the final velocity of the pencil? How long will the pencil be in free-fall? Round your answers to 1 decimal place.
4.3 m/s down; 0.4 sec
For a free-falling object, the velocity ________ at a ________ rate.
increases; constant rate of -9.8 m/s2
If the sign of v is negative and the sign of a is positive, what direction is the object traveling and is it speeding up or slowing down?
negative direction; slowing down
An object travels at a constant velocity of 4 m/s for the time period from 0 to 10 seconds. What is the instantaneous velocity at time t = 3 seconds?
4 m/s