The Kinematic Equations

Kinematics

Describes motion without regard to what causes it.Uses equations to represent the motion of an object in terms of acceleration (a), velocity (v), displacement (d) and time (t).

Equations

vf = vi + at d = (vf + vi)t

2

d = vit + ½at2 vf2 = vi

2 + 2ad

If a car’s initial velocity is +25 m/s, and it accelerated at a rate of +7.5 m/s2 over a period of 8.0 seconds what is the car’s final velocity? vf = 85 m/s

vf = vi + at

If a kicker boots the ball at a velocity of +45 m/s and it is aided by a gust of wind to accelerate at +2.5 m/s2 and it stays in the air for 3.5 seconds. How far will the ball travel? d = +170 md = vit + ½at2

A boy sledding down a hill has an initial speed of +12m/s. He continues to speed up and reaches a final velocity of +18m/s after traveling for 12 seconds. What distance does the boy travel. d = +180 m d = (vf + vi)t

2

Mr. Billante is notorious for his road rage. After being cut off he accelerates at a rate of +12.3 m/s2 for +455 m. As he approaches the man who cut him off his final velocity is a ludicrous +125 m/s. What was his initial velocity? vi = +66.6 m/s

vf2 = vi

2 + 2ad

Free Fall

An object is in Free Fall if gravity is the only force acting on an object. (Assume no Air Resistance) g = acceleration due to gravity on a particular planet g = - 9.8 m/s2