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Using the Acceleration Formula - Basics

Useful Information:

  1. Just Give Us the Answer Already. These problems are mostly solved already. Just complete the last step. Include the unit to make your answer all complete and happy!
  2. A roller coaster’s velocity at the top of the hill is 10 m/s. Two seconds later it reaches the bottom of the hill with a velocity of 26 m/s. What is the acceleration of the coaster?

Known Quantities
t=2s, vo=10 m/s
vf=20 m/s / Symbolic Formula
/ Quantities “plugged in”
/ Answer, with units
  1. How long will it take a car to go from 0 to 12 m/s if they are accelerating at 4 m/s2?

Known Quantities
vf=12m/s, vo=0m/s, a=4m/s2 / Symbolic Formula
/ Quantities “plugged in”
/ Answer, with units
  1. A rocket takes off from rest, accelerating at 180 m/s2 for 1.5 seconds. How much does its velocity change?

Known Quantities
a=180m/s2
t=1.5 s / Symbolic Formula
/ Quantities “plugged in”
/ Answer, with units
  1. Substitute Teacher. Learn how to substitute known quantities by looking at the examples above. The do the same for the problems below. Remember to find the answer, too! Remember units, for both the answer and the quantities you plug in.
  2. A dog skids to a stop on ice, accelerating at –0.5 m/s2 for a time of 4.5 s. What was the dog’s original velocity?

Known Quantities
a= –0.5 m/s2
t=4.5 s / Symbolic Formula
/ Quantities “plugged in” / Answer, with units
  1. Calculate the acceleration of a turtle going from 0.3 m/s to 0.7 m/s in 30 seconds.

Known Quantities
t=30s, vo=0.3 m/s
vf=0.7 m/s / Symbolic Formula
/ Quantities “plugged in” / Answer, with units
  1. A car drives along at 20 m/s slams on its brakes, accelerating at –9 m/s2. How long does it take the car to stop?

Known Quantities
vo=20m/s, vf=0m/s, a=–9m/s2 / Symbolic Formula
/ Quantities “plugged in” / Answer, with units
  1. The Secret Code. You need to write the directions used to solve each word problem. These directions are written in the form of a “symbolic formula.” It’s kind of a secret code that physics-savvy folks know, and it allows you to write the instructions in just a few letters and symbols. The previous sections give some examples.
  2. Calculate the time it takes to gain 30 m/s of speed with an acceleration of 6m/s2.

Known Quantities
v=+30m/s, a=–9m/s2 / Symbolic Formula / Quantities “plugged in” / Answer, with units
  1. Calculate the velocity change of an apple that falls freely* for 0.8 seconds.

Known Quantities
a=g=10m/s2, t=0.8s / Symbolic Formula / Quantities “plugged in” / Answer, with units
  1. An emu takes 4 seconds to go from 0 m/s to 6 m/s. Set up an appropriate calculation.

Known Quantities
t=4s, vo=0m/s, vf=6m/s / Symbolic Formula / Quantities “plugged in” / Answer, with units
  1. A boat slows down from 12 m/s to 7 m/s, with an acceleration of –2.5 m/s2. How much time did that take?

Known Quantities
a=-2.5m/s2, vo=12m/s, vf=7m/s / Symbolic Formula / Quantities “plugged in” / Answer, with units
  1. Put It All Together. Start by writing the known quantities. These are the amounts given in the problem (with units!). Did you notice the examples above?
  2. A coconut falls freely* from a tree. It plummets for 2 seconds before hitting you on the head. How fast was the coconut going when it struck you?

Known Quantities / Symbolic Formula / Quantities “plugged in” / Answer, with units
  1. A train starts from rest, and it accelerates at 0.2 m/s2 until it reaches a speed of 24m/s. Make an appropriate calculation based on this information.

Known Quantities / Symbolic Formula / Quantities “plugged in” / Answer, with units
  1. A cannonball in an old-fashioned cannon takes about 0.001 seconds to reach a speed of 250 m/s. Make an appropriate calculation based on this information.

Known Quantities / Symbolic Formula / Quantities “plugged in” / Answer, with units

*Hmm, “falls freely.” That tells you something about the acceleration, right?