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Explore the concept of acceleration and its relationship with velocity and time. Learn how to calculate acceleration, differentiate between positive and negative acceleration, and understand the units and formulas involved. Watch videos and access additional resources to gain a comprehensive understanding of this fundamental concept in physics.
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Objective • I will analyze and interpret data • So that I can show the relationship between acceleration, velocity, and time • By highlighting cause and effect
Acceleration Acceleration is defined as the change in velocity over time.
Acceleration Any time an object's velocity is changing, we say that the object is accelerating.
Acceleration This brings up an important point. In common language, when things speed up, we say that they are "accelerating," and, when they slow down, we say that they are "decelerating."
Acceleration • However, in the language of physics, we say that both objects are accelerating, not because both objects are speeding up, but because both objects have changing velocities.
Acceleration • POSITIVE ACCELERATION (SPEEDING UP)
Acceleration * NEGATIVE ACCELERATION (DECELERATING) SLOW DOWN
An object will accelerate when there is a net (or unbalanced) force acting upon it. Acceleration is a vector and is in the same direction as the net force.
The first car is accelerating (speeding up) to the right. Its velocity has increased from 30km/h to 60km/h.
The second car is decelerating (slowing down) to the left. Its velocity has decreased from 60km/h to 0km/h. The direction of the acceleration (in this case deceleration) is to the left as a net force in this direction causes the car to slow down. If the direction to the right is labeled as the positive + direction, then left is the negative - direction, then you would write this deceleration with a negative value. E.g. -2.0m/s2
The cyclist below is accelerating. His velocity is increasing by 1 m/s each second. Therefore we can say that he is accelerating at a rate of one meter per second per second = 1 m/s2.
Units • Calculating acceleration involves dividing velocity by time — or in terms of units, dividing meters per second [m/s] by second [s]. Dividing distance by time twice is the same as dividing distance by the square of time. Thus the SI unit of acceleration is the meter per second squared.
Units • We can think of acceleration as doing two things at once. We are still moving across a distance over a time, but we are also increasing how fast we are doing it. We are multi-tasking to arrive sooner, so we have to multiply the time x time to calculate the correct numerical value for our acceleration.
Units explained V= m/s A= v/t = m/s/s = m/s x 1/s = m / s x s =m/ s2 And the result is meters per second squared
(change) in velocity acceleration = time Acceleration is defined as the change in velocity over time.
final velocity – initial velocity acceleration = time Acceleration is defined as the change in velocity over time.
Vf - Vi a = t Acceleration is defined as the change in velocity over time.
Formula Plug-in Answer A go-cart started from the top of a hill at 5 meters per second. At the bottom of the hill it ended up with a speed of 35 meters per second 6 seconds later. What was the acceleration of the go-cart? 5 m/s Step 1 Read the problem. Draw a picture. top Vf = In 6 s Vi= t = a = bottom 35 m/s
A go-cart started from the top of a hill at 5 meters per second. At the bottom of the hill it ended up with a speed of 35 meters per second6 seconds later. What was the acceleration of the go-cart? Formula Plug-in Answer Step 2 Write down what you know. What are you trying to find? Start: initialVelocity final velocity – initial velocity 5 m/s top acceleration = time 35 m/s Vf = 6 s Vi= 5 m/s t = 6 s ? a = Finish: final Velocity bottom 35 m/s
A go-cart started from the top of a hill at 5 meters per second. At the bottom of the hill it ended up with a speed of 35 meters per second6 seconds later. What was the acceleration of the go-cart? Formula Plug-in Answer Vf - Vi Vf - Vi t t top Step 3 Set up the formula. Start: initialVelocity 5 m/s 6 s 35 m/s Vf = Vi= 5 m/s t = 6 s ? a = Finish: final Velocity bottom 35 m/s
Formula Plug-in Answer Vf - Vi t A go-cart started from the top of a hill at 5 meters per second. At the bottom of the hill it ended up with a speed of 35 meters per second6 seconds later. What was the acceleration of the go-cart? Step 4 Plug-in the numbers. Solve. Start: initialVelocity 5 m/s top 35 m/s Vf = 6 s Vi= 5 m/s 35m/s– 5 m/s 30 m/s 5 m/s2 t = 6 s = 6 s 6s a = 5 m/s2 Finish: final Velocity bottom 35 m/s
Constant Speed of 55 mph Think Differently About Acceleration 1. Consider a car moving at a constant speed of 55 mph while turning in a circle. 2. The car's velocity is not constant, even though the speed is constant. 3. WHY? This is because the direction of motion is constantly changing while the car is turning around the track. 4. Since the direction is changing, even though the speed is not, the velocity is changing (velocity involves bothspeed and direction).
https://www.youtube.com/watch?v=vxFYfumAAlY https://www.brainpop.com/science/motionsforcesandtime/acceleration/
