150 likes | 269 Views
Motion in 1D. From the Simpsons. Imbalance of forces. We have talked a lot about Forces being balanced. When forces are unbalanced it results in the object accelerating. Distance.
E N D
Motion in 1D From the Simpsons
Imbalance of forces • We have talked a lot about Forces being balanced. • When forces are unbalanced it results in the object accelerating.
Distance • Any time an object moves it moves a distance. In the picture the Simpson family has moved a distance from their house. • This is measured in meters, and is always positive. • A scalar quantity
Displacement • The change in the position of the particle • Homer gets up from the couch and goes to the refrigerator. Then he comes back. His displacement is zero • Measured in meters • A vector quantity
B A Displacement Example • Homer is chasing Bart around the house. He catches him at point B, What is the distance and displacement?
Speed • Think of your car • Speed is change in distance over the change in time. • Measured in Meters/sec • Always positive • A scalar quantity
Velocity • Like speed, but with another component: Direction • Measured in m/s • A vector Quantity • Velocity is important when you are trying to go to a specific destination.
Velocity Formula V = displacement change in time
Velocity Problem • Marge leaves from the store. She travels 1 km for 10 m/s west. Then she needs to pick up the pace and get home before Homer does. She increases her velocity to 20 m/s west for 1 km. What is her average velocity
Acceleration • Is what happens when you change velocity over time. • Measured in m/s2 • A vector quantity • Is the result of imbalanced forces • Can result when • You speed up/ slow down • Turn • We assume that this is uniform • Has a sign (+ or -)
Sideshow Bob has escaped • Bart gets on his bike to escape the madman and goes from rest to 10 m/s in 10 seconds. What is his average acceleration
Braking • Marge is moving at 10 m/s when she has to hit the brakes to avoid a boy on a skateboard. How long does it take her to stop if her average acceleration is -5 m/s2
Free Fall • Free fall is another example of 1D motion just in the Y direction • The acceleration in these problems is known: • -9.8 M/S2 • The acceleration due to gravity • Typically seen as a negative value due to the fact that gravity pulls down