SPEEDBY HASHIM ALICLASS 7 (A)

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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.

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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.

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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.

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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 !

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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.

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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.

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EXAMPLES OF DISTANCE/TIME GRAPHS

• KEY POINT: SLOPE=SPEED

• 1. WHEN SLOPE IS CONSTANT, SPEED IS ALSO CONSTANT.

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2. WHEN SLOPE IS INCREASING, SPEED ALSO INCREASES.

EXAMPLES OF DISTANCE/TIME GRAPHS

• KEY POINT: SLOPE=SPEED

• 3. WHEN SLOPE IS DECREASING, SPEED ALSO DECREASES.

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2. WHEN SLOPE IS ZERO, SPEED IS ZERO WHICH MEANS THAT OBJECT IS AT REST.

Time

SPEED RECORDS

• People trying to beat the land speed record must drive their vehicle at full speed between two markers.

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DATE SPEED/km/h DRIVER VEHICLE

15/10/97 1227.99 Andy Green Thrus t SSC

4/10/83 1013.47 Richard Noble Thrus t 2

23/10/70 995.85 Gary Gabel i ck The Blue Flame

15/11/65 960.96 Cra ig Breed love Spir i t Of Ameri ca

7/11/65 922.48 Art Arfan Green Mons ter

VELOCITY

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

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