2. Change in Velocity Each time you take a step you are changing the velocity of your body. You are probably most familiar with the velocity changes of a moving bus or car. The rate at which velocity (speed or direction) changes occur is called acceleration.
3. Acceleration= final velocity- starting velocity time Change in velocity = final – starting velocity velocity Acceleration= change in velocity time
4. A car traveling at 60 mph accelerates to 90 mph in 3 seconds. What is the car’s acceleration? Velocity(final) - Velocity(original) = Acceleration time 90 mph - 60 mph = 3 seconds 30 mph = 3 seconds = 10 mph/second
6. A car traveling at 60 mph slams on the brakes to avoid hitting a deer. The car comes to a safe stop 6 seconds after applying the brakes. What is the car’s acceleration? Velocity(final) - Velocity(original) = Acceleration time 0 mph - 60 mph = 6 seconds - 60 mph = 6 seconds = - 10 miles per hour per second
7. - A constant acceleration produces a straight line or linear slope (rise/run). - The slope of a non-linear velocity-time graph (rise/run) will predict an objects instantaneous acceleration. a = v/t
8. Free fall The constant acceleration of an object moving only under the force of gravity is "g". The acceleration caused by gravity is 10 m/s2 If there was no air, all objects would fall at the same speed Doesn’t depend on mass After 1 second falling at 10 m/s After 2 seconds 20 m/s 3 seconds 30 m/s
9. Falling Air resistance will increase as it falls faster An upward force on the object Eventually gravity will balance with air resistance Reaches terminal velocity - highest speed reached by a falling object.
