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Kinematic Equations and Introduction to F reefall motion . Since the average acceleration is equal to instantaneous acceleration, we can rewrite the acceleration as the following:.
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Since the average acceleration is equal to instantaneous acceleration, we can rewrite the acceleration as the following: Unless otherwise specified, let ti =0s. Also for our own convenience, we are going to replace vf with v and vi with vo. With a little algebra the equation can be rearranged to find the final velocity.
We can write the equation for average velocity as the arithmetic average of the initial velocity (vo) and final velocity (v). Knowing this previous equation and that Where xi and ti both equal to 0Then rearrange for x.
So Plug the equation for average velocity in and you get: A little algebra and the equation simplifies to Using Plug in for v And simplify
into Substitute And solve for v2
Freefall Is when an object is moving under the influence of gravity alone. The source of the initial motion is not important. Objects that are thrown upward, downward or released from rest are all in freefall once released.
Once objects are in freefall they have a constant acceleration downward, which is the acceleration due to gravity, g. • g=9.8m/s2 • g is + or – depending on the definition of the + direction
Freefall Practice Problems 1. A ball is thrown downward from the top of a cliff with an initial speed of 10.0 m/s. Determine the velocity and speed of the ball ay t=2.00s.
Freefall Practice Problems • A stone is thrown from the top of a building with an initial velocity of 20.0 m/s upward. The building is 50.0m high, and the stone just misses the edge of the roof on the way down. Determine • the time to reach the maximum height. • the maximum height. • the time needed to return to the throwers height. • the velocity of the stone at this height. • the velocity and position of the stone at t = 5.00s.