Speed is a measure of the distance covered by an object in a certain time, usually measured in m/s and km/h. There are several ways to measure speed, including using a speedometer, speed trap gun, stopwatch, and light gates. A distance/time graph can also be used, where the slope of the line represents speed - a constant slope means constant speed, an increasing slope means increasing speed, and a decreasing slope means decreasing speed. Several land speed records have been set by drivers trying to beat previous top speeds between two markers.

1. SPEED
BY HASHIM ALI
CLASS7 (A)

2. What basically is SPEED ?!
• Speed is a measure of the distance
covered by an object in a certain time!
• It is usually measured in m/s and km/h.

3. MEASURING SPEED 
1. THE SPEEDOMETER
• A speedometer or a speed meter is a gauge that
measures and displays the instantaneous speed of a
vehicle.
• Speedometers for other vehicles have specific names
and use other means of sensing speed. For a boat, this
is a pit log. For an aircraft, this is an airspeed indicator.

4. 2. The speed trap gun
• A speed trap gun is a radar gun. When the gun is fired at
an approaching vehicle, a beam of radio waves travels
through it to the air.
• A computer in the gun compares the time difference
between sending the beam and receiving it back from
the vehicle and calculates the vehicle’s speed.

5. The 3._____ WHAT? 
STOPWATCH! 
• A stopwatch is a handheld timepiece designed to
measure the amount of time elapsed from a particular
time when it is activated to the time when the piece is
deactivated.
• The distance travelled from the start line to the finish line
is measured and then divided by the time measured by
the stop watch.
• What this gives? SPEED OF THE OBJECT !

6. 4. LIGHT GATES
• In a light gate, a beam of light shines onto a light-
sensitive switch. When the beam of the light gate used at
the start of a speed test is broken by an object passing
through it.
• When a beam of the light gate used at the finish of the
speed test is broken by an object passing through it, it
causes the stop watch to be stopped.
• The speed of the object is then found by dividing the
distance between the light gates by the time as
measured by the stop watch.

7. DISTANCE/TIME GRAPHS
• The distance travelled by an object over a period of time
can be plotted on a graph called a distance/time graph.
• The gradient of a distance-time graph represents the
speed of an object.

8. EXAMPLES OF DISTANCE/TIME GRAPHS
• KEY POINT:
SLOPE=SPEED
• 1. WHEN SLOPE IS
CONSTANT, SPEED IS
ALSO CONSTANT.
2. WHEN SLOPE IS
INCREASING, SPEED
ALSO INCREASES.

9. EXAMPLES OF DISTANCE/TIME GRAPHS
• KEY POINT:
SLOPE=SPEED
• 3. WHEN SLOPE IS
DECREASING, SPEED
ALSO DECREASES.
2. WHEN SLOPE IS
ZERO, SPEED IS
ZERO WHICH MEANS
THAT OBJECT IS AT
REST.
Time

10. SPEED RECORDS
• People trying to beat the
land speed record must drive
their vehicle at full speed
between two markers.
DATE SPEED/km/h DRIVER VEHICLE
15/10/97 1227.99 Andy Green Thrust SSC
4/10/83 1013.47 Richard Noble Thrust 2
23/10/70 995.85 Gary Gabelick The Blue Flame
15/11/65 960.96 Craig Breedlove Spirit Of
America
7/11/65 922.48 Art Arfan Green Monster

11. VELOCITY
• The velocity of an object
is its speed and its
direction of movement.