Motion in 1-Dimension

1
Motion in 1-Dimension

• (Objects that are moving in the x direction or y
  direction only!)

2
Variables

• Time How long an object does something (sec)
• Distance How far an object travels (m)
• Velocity How fast an object travels (m/sec)
• Vi Initial velocity
• Vf Final velocity
• Acceleration How the speed of an object changes
  over time (m/sec2)

3
Acceleration

• Acceleration- For most of our problems, you will
  need to know the acceleration
• Object falling towards the Earths surface a
  __________
• That means that as an object falls towards the
  Earth, its speed is
•  
•  
• If the object is not falling, we need to
  calculate the acceleration using an equation.

4
The Equations

• 1. 3.
•  
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• 2. 4.
• How do I know which equation to use?
•  
• Is the velocity constant? __________________ If
  yes- use 1
• If not, use any of the other 3 that you have
  enough information to solve.

5
Tips for Solving Problems

• Anything down is ______________________________
• Often you know some of the velocities right away
• If an object starts at rest, Vi
  __________________
• If an object stops, Vf ________________
• If you throw an object up, what is its speed at
  the top? _____
• If an object is dropped, we know 2 things
• Vi _____________________ a
  ____________________
• Time up Time down (If thrown and caught at
  same height)
• (If you throw an object up and it takes 6 sec to
  land back in your hand, how long did it take to
  go up? ________________

6

• Problem 1 Tommy drops a bottle from a height
  of 1.4 meters. How long will it take to reach
  the ground?
• Given
• Unknown
•  
• Equation

7

• Problem 2 Pikachu is battling Chimcharm. If
  Pikachu accelerates from rest at a rate of 1.5
  m/s2, what will his final velocity be when he
  gets 25 meters away?

8

• Problem 3 Megatron is trying to catch up to
  Optimus Prime after a battle against the
  Decepticons. He gets on a motorcycle and reaches
  a velocity of 16 m/s. Suddenly he realizes he is
  going to hit a brick wall (63 meters away) which
  he is unable to turn away from. He shuts the
  motorcycle off and coasts to a stop. Calculate
  the deceleration he will have to undergo in order
  to stop just before the wall. (deceleration is
  just a negative acceleration)

9

• Problem 4 Spongebob (as a caveman) drops a rock
  off a cliff. If it takes 3.5 seconds for the
  rock to hit the ground, calculate
• a) the velocity at which the rock is traveling
  just before it hits the ground in m/s and in
  miles per hour.
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• b) the height of the cliff.