Acceleration

1. Acceleration-the rate at which velocity changes over time; an object accelerates if its speed, direction, or both change 2. Ex of acceleration in real world-bus is decelerating when it approaches a bus stop; acceleration of a train from when it leaves the station until it gets out in the open 3. Change in velocity- change in velocity is found by getting V final - Vinitial and dividing by Tfinal and Tinitial 4. Rate at which Velocity changes per time interval-this is found by taking velocity over time and getting m/s/s so for every second there is a direct change in m/s 5. m/s/s are the units of acceleration 6. They would feel the bus decelerating to a stop faster because it is taking less time to come to a complete stop 7. If an object is moving to the right with a positive velocity it will have a positive acceleration, but if that same object starts to slow down the velocity will be negative because Pinitial is greater than Pfinal and acceleration will be negative. 8. change in velocity over change in time equals acceleration 9. constant acceleration is when the velocity and time are changing at equal intervals each time to keep it constant where average acceleration is the change in velocitys divided by the change in time so if the intervals of change are different it will not be equal to constant acceleration 10. When an object is acclerating for equal time intervals the displacement is increasing with each time interval because as time goes on an object keeps accelerating and it takes less and less time to reach a certain displacement. The position vs. time graph shows this on the ball motion lab as the ball got to farther displacements it took less time to get there as it rolled down the hill. The equation for this is shown by the equation y=0.3767x(squared) + 0.0244x + 0.014 which shows that for every x increase (time) the y (position) increases 11. Velocity is directly affected by the time intervals when moving with a constant acceleration and is show by a linear relationship on a graph so when time intervals change positively with constant acceleration velocity is increasing equally with each interval. The velocity vs. time graph on the ball motion lab shows this relationship with a linear regression line through the data points and the equation is the basic y=mx+b form


 * Freefall:**
 * 1) When an object is in freefall the velocity is increasing at a constant rate for every second that goes by (in Group 2 Trial 2 graph for every about .1 second increase velocity goes up by about .2 m/s)
 * 2) An object that falls for about one second is going about 21.9 mi/hr
 * 3) No different masses do not affect velocity because of the constant acceleration of gravity on all freefalling objects
 * Up and Down Motion:**
 * 1) The red line indicates the velocity in this motion and in this case the velocity is change at a rate of -9.81 m/s/s because acceleration is constant and the slope of velocity vs. time graph represents the acceleration. The object is slowing for about 2.5 sec and once the velocity goes to negative the object is moving in a positive direction again.
 * 2) The rate at which velocity changes is shown by the green line representing acceleration because the slope of velocity vs. time graph is the acceleratoin
 * 3) About 25 m/s is the initial velocity
 * 4) Speed at max height is the same as starting speed because velocity is decreasing on the velocity vs. time graph due to negative acceleration
 * 5) The speed on the graph says -25 m/s but that is not accurate because velocity initial is decreasing at a rate of 9.81 m/s/s but because velocity becomes negative and acceleration is constant the object is again speeding up one is reaches negative, so the final speed is 25 m/s for when the object hits the ground (negative sign just means it is coming down).