Name the formula for acceleration and apply it in calculations.
Be able to rearrange the formula for acceleration.
Define the unit of acceleration.
Be able to read speed-time graphs
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Recap
What is acceleration?
Examples of acceleration?
How do you calculate acceleration?
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acceleration=timefinalspeed−startingspeed
a=tvf−vi
a: acceleration
vf: final speed
vi: initial speed
t: time
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The unit of Acceleration
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Unit of Acceleration
speed/time
(m/s)/s
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Unit of Acceleration
speed/time
(m/s)/s
m/s
2
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Acceleration
Exercise
A dragon fly is flying at a speed of 15,6 m/s. A strong wind pulls up bring its speed down to 12,9 m/s 5 seconds later. Calculate its acceleration.
a=tvf−vi
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Discussing the homework
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3. A spaceship is travelling at 20,000.0 m/s. After 5.0 seconds, the rocket thrusters are turned on. At the 55.0 second mark, the ship has a velocity of 24,000.0 m/s. What is the acceleration of the rocket?
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3. A spaceship is travelling at 20,000.0 m/s. After 5.0 seconds, the rocket thrusters are turned on. At the 55.0 second mark, the ship has a velocity of 24,000.0 m/s. What is the acceleration of the rocket?
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4. The gravitational force on Mars is much lower than the gravitational force on Earth (acceleration due to gravity on Earth accelerates falling objects at 9.8 m/s2). If a dropped hammer’s speed increases from 0.0 m/s to 15.0 m/s in 4.04 s, what is the acceleration due to gravity on Mars?
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4. The gravitational force on Mars is much lower than the gravitational force on Earth (acceleration due to gravity on Earth accelerates falling objects at 9.8 m/s2). If a dropped hammer’s speed increases from 0.0 m/s to 15.0 m/s in 4.04 s, what is the acceleration due to gravity on Mars?
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Rearranging the formula for acceleration
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Rearranging the formula
acceleration=timechangeInspeed
3=26
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Rearranging the formula
A cyclists accelerates at a rate of 1.26 m/s2 for 6.3 seconds. Calculate his change in speed
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Exercise 1) Elevators in in the Yokohama tower in Japan are among the fastest in the world. They accelerate upwards at a rate of 3.125 m/s2 for 4 seconds. Starting from rest, what is their final speed? Exercise 2) A cyclists starts a sprint. he accelerates at a rate of 0.325 m/s2 for 12 seconds. He ends up reaching a speed of 9.7 m/s. Calculate his starting speed.
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Speed-time graphs
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Speed-time graphs
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What type of movement is shown at each part of the graph?
A: Steady acceleration
B: Steady speed
C Steady acceleration
D: increasing acceleration
E Decreasing acceleration
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Homework
Worksheet acceleration Exercise 5, 6, 7, 8
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Learning goals
Name the formula for acceleration and apply it in calculations.
Be able to rearrange the formula for acceleration.