Review Test #2: Constant Acceleration

Reading: Ch. 3, p.p. 56-79

Topics: Change in Velocity, Definition of Acceleration, v-t graphs,

Constant Acceleration Equations, Falling Bodies

Labs & Activities: Ball on Incline, Carts on Incline, Picket Fence, Ball Toss

Equations:a = Δ vv2 = v1 + atΔ d = v1t + ½at² v2² = v1² + 2a Δ d

t

Objectives:

  • Be able to read velocity-time graphs
  • Be able to identify examples of acceleration.
  • Use constant acceleration equations to solve problems.

Solutions should include:

List of known and unknown information with symbols and units.

Formula used in equation form.

Final answers with correct sign and units.

  • Be able to use g = 9.8 m/s² to solve problems with falling objects.
  • Be able to solve problems when objects are thrown straight up into the air.
  • Be able to answer thinking questions about falling objects.

Review Questions/Problems

2. An object moves in the negative direction

with an acceleration of + 6 m/s². Explain

what is happening to the object’s motion.

3. A ball rolls along a level surface at a constant velocity and then accelerates down a ramp at a rate of 3.0 m/s². The ramp is 7.0 m long and the ball is moving at 8.2 m/s at the bottom. How fast was it traveling at the top of the incline? Assume down the ramp is the + direction.

4. A balloon is descending at a rate of 12.0 m/s and is 78 m above the ground when a package is dropped from it. With what speed does the package hit the ground?

5. Consider the velocity vs. time graph shown. What is the acceleration of object A and object B at 5 seconds.

  1. Bonnie and Clyde stand together on a high balcony and fire their guns at the same time. Bonnie fires straight down with a velocity of 200 m/s while Clyde fires straight up with the same velocity.

a)Whose bullet will be in the air the longest?

b)Whose bullet will hit the ground with the fastest velocity?

c)Whose bullet has the greatest acceleration?

7. A pop-up toy leaves a 1-m high table with a velocity of 3.7 m/s.

a)If it goes straight up into the air and falls back to the table, what is its hang time?

b)How high above the table does it go?

c)If the toy misses the table on the way down and falls to the ground, what is its velocity when it reaches the ground?

8. Answer the following questions about the position vs. time graph shown.

9. A car travels at 22 m/s for 5 minutes. Suddenly a tractor pulls out in front of the car, forcing the car to slow to 6 m/s in just 2 seconds. The car continues at this speed for 1 minute until the tractor turns off onto a side road. The car then gradually accelerates at 0.5 m/s² for 25 seconds. Hint: Make a list of knowns for each different part of the situation.

a)How far did the car travel while slowing to avoid hitting the tractor?

b)What is the final velocity of the car?

c)How far total did the car travel?

d)What was the total time of the car’s trip?

e)Make a velocity-time graph for the car’s trip.