Types of Motion 1 2 Velocity v = ../… v2 - v1 vf - vi = t2 - t1 A - ......................VELOCITY – constant displacement every second. 1 2 ... . . . . . . . . . . . . . . . . . . . . . . . . . .. . .... s1 s2 Velocity v = ../… displacement x = x2 - x1 Time t = t2 - t1 B - ............................ Motion v1 = vi v2 = vf -- - - - - - - - - --> s t1 = 0 t2 = t vf = vi + …t x = vi t + ½… t2 vf2 = vi2 + 2…. x a = v t = v2 - v1 t2 - t1 vf - vi s = (vi + vf) 2 t

Equations of Motion .. . . . . . t vf vf = vi+ at vf2 = vi2 + 2ax x = vit + 1/2at2 x = ((vf+ vi)/2)t vi = ………..velocity (m.s-1) vf = ……….velocity (m.s-1) x = ………………………(m) a = acceleration (m.s-…..)  t = time (…..) a >0 vi .. . . . . . x t Write down all the symbols for values you COULD be given. Choose a + direction. Write down the values you WERE given. Rest = 0! Write down what you were asked. Identify an equation that includes all these quantities. Substitute into the equation and solve. (UNITS for ANS!) Negative acceleration = slowing down!

Equations of motion examples A car traveling at 4m.s-1 is accelerated uniformly at a rate of 3m.s-2. What distance, from when the acceleration began, will the car have traveled in 5s? An aircraft, flying at an unknown initial velocity, accelerates uniformly at the rate of 5m.s-2. It reaches a velocity of 200m.s-1 after accelerating over a distance of 3000m. Calculate the initial velocity of the aircraft. A car traveling at 30m.s-1 is brought to a stop in 6s by application of its brakes. Assuming that the acceleration is uniform calculate: the displacement while the brakes are being applied the acceleration

Equations of motion examples A car traveling at 4m.s-1 is accelerated uniformly at a rate of 3m.s-2. What distance, from when the acceleration began, will the car have traveled in 5s? GIVEN: ASKED:

Equations of motion examples An aircraft, flying at an unknown initial velocity, accelerates uniformly at the rate of 5m.s-2. It reaches a velocity of 200m.s-1 after accelerating over a distance of 3000m. Calculate the initial velocity of the aircraft.

Equations of motion examples A car traveling at 30m.s-1 is brought to a stop in 6s by application of its brakes. Assuming that the acceleration is uniform calculate: the displacement while the brakes are being applied 2. the acceleration

Substitution Example (s & m p55 no9) Car X , starting from res. at point A, accelerates at 5m.s-1 for 6 seconds along a straight horizontal road in the direction of point B. After 6s it continues further at a constant velocity. At the same instant that car X starts moving, car Y drives past point B (1200m from point A) on the same road in the direction of A at a constant velocity of 20m.s-1 1200m A B v (m.s-1) t (s)

Speed vs Stopping Distance Homework task Find information on the factors affecting stopping distance of a car. Also research safety measures which are built into cars to ensure the safety of the occupants in the event of collisions. Explain how the safety features relate to speed, stopping distance and force.

Speed vs Stopping Distance What does this graph tell us?