Linear Acceleration 12th grade Physics Class What are we doing? Learning Objectives • We are going to learn a couple of Newtonian Physics equations that.
Download ReportTranscript Linear Acceleration 12th grade Physics Class What are we doing? Learning Objectives • We are going to learn a couple of Newtonian Physics equations that.
Linear Acceleration
12 th grade Physics Class
Learning Objectives
• We are going to learn a couple of Newtonian Physics equations that will allow us to calculate values of time, acceleration, displacement, and velocity for objects accelerating in a straight line.
Using Equations
• • • Newtonian equations that have been derived from basic physics laws can be used to easily relate acceleration, time, velocity, and displacement.
An unknown value can be found by inserting known factors for the rest of the variables.
These are the variables that will be seen in the equations -------------- V f = final velocity (m/s) V i = initial velocity (m/s) a = acceleration (m/s*2) t = time (s) d = displacement (m)
Linear Acceleration Equations
•
V f = V o + at
This equation relates the change in velocity and acceleration to time •
V f *2 = V o *2 + 2ad
This equation relates the change in velocity and acceleration to displacement
I’m ready to see them in action!
Example Problem: If a ball is dropped from cliff, how fast will it be traveling after 4 seconds? (ignore air resistance) • First, find the known variables: • • We know the time the ball is traveling is t=4s The acceleration of a falling object is the same as gravity, a=9.8m/s*2 We know the initial velocity of the ball, V
o =0m/s
Now plug them into the equation to find the final velocity: V f = 0m/s + (9.8m/s*2 x 4s) Using basic math, we find that final velocity = 39.2m/s Now you try!
A car at rest begins to accelerate at a constant rate of 6m/s*2. How long will it take the car to reach a speed of 24 m/s?
Incorrect!
Make sure you’re using the right equation and remember to check your math and units!
That’s right!!
You should have used the equation: V f = V o + at
A boy throws a rock directly downward at a speed of 5m/s off the roof of a building. When it hit the ground, the rock was moving at a staggering 73 m/s. Negating air resistance, how tall was the building?
Incorrect!
Remember, the rock had an initial velocity that needs to be accounted for
That’s right!!
You should have used the equation: V f *2 = V o *2 + 2ad