Average Velocity (def):  Equal to the rate of change of displacement over a period of time.                                                       

v_avg = d/ t  

Instantaneous Velocity (def):     Equal to the rate of change of displacement at any given instant in time (the slope of the displacement vs time graph for the motion at a given time value.  

Acceleration (def):  When the velocity of an object is changed, that object experiences an acceleration.  The amount of acceleration experienced depends on how much the acceleration is changed and in how much time the change occurs.                                                             

Gravity: An object that falls on Earth accelerates.  The acceleration of gravity (gravitational field strength, g) depends on the distance that the object is located from the center of mass of the Earth; however, near the surface of the Earth, the rate of acceleration of falling objects (neglecting air friction) is approximately g = 9.8 m/s². On the moon, since the mass of the moon is 1/6 of that of the earth, so is the acceleration of gravity (g_moon = 1.6 m/s²).

Check out this video clip showing that a feather and a hammer will fall at the same rate when there is no air (as is the case on the moon):   Equations:                                        d = v_it + ½ at²                                                           v_f = v_i + at                                                           v_f² = v_i² + 2ad 

Problem Solving:  Students should organize each problem as it is attempted.  A method such as "VIFDAT" should be used:

1. Record all information given in a list of variables like the following:  

v_i  =
v_f =
d =
a  =
t   =  

2. Find the equation that has both the unknown and the given information and manipulate to solve for the unknown.
3. Manipulate the equation in variables before entering numeric information.    

The following are some examples of problem types that will be encountered in physics 11 Kinematics (one dimension):    

Constant velocity:  

1. An object travels at 5 m/s for 5 seconds; how far will the object travel?
2. How long does it take the Concord Jet to travel 2150 km if it travels at a speed of 1500 km/hr?    

Changing Velocity: 

3. If a car which is moving at a rate of 25 m/s wishes to stop in 2.5 seconds, how much distance will he cover in doing so?   
   
4. If a ball is thrown vertically (upward) at a rate of 30m/s:
   a)  How high does the ball go?  
   b)  How long is it in the air before it returns to the ground?   
   
5. If a rock falls out of a plane which is moving at 50m/s at an altitude of 3000 m, how long does it take to hit the ground (assuming no friction)?  

Kinematics 11 Links