Speed What is it?

OUTCOMES State what speed means Estimate some speed values Calculate speeds using formula Rearrange the formula to calculate time and distance. Describe the difference between speed and velocity. Calculate velocity when objects are moving relative to each other

Match the speed to the picture Continental drift 21 km/h 0.00000004 km/h 0.004 km/h 917 km/h 36 km/h 119 km/h

Match the speed to the picture Continental drift 6 m/s 0.00000001m/s 0.001 m/s 1m/s is about 3.6 km/h 255 m/s 10 m/s 33 m/s

......20mph (9m/s) in a residential area Speed limits ......20mph (9m/s) in a residential area ......70 mph (31 m/s) on a motorway

The speed of a tennis serve...... ......over 55m/s or 200km/h

The speed of sound......... ......over 300 m/s

Breaking the sound barrier...

Escape velocity...... ......about 11200 m/s

The speed of light......... ......300,000,000 m/s

How do we calculate speed? https://www.youtube.com/watch?v=3nbjhpcZ9_g Usain Bolt ran 100m in 9.58s. What was this record breaking speed?

How is speed calculated? The speed of an object can be calculated using this equation: distance travelled time taken speed = Distance travelled is measured in metres (m). Time taken is measured in seconds (s). Speed is measured in metres per second (m/s). The standard unit for speed in physics is m/s, but other units such as kilometres per hour (km/h) are more convenient when measuring the speed of vehicles. Why is this?

How do we calculate speed? Usain Bolt ran 100m in 9.58s. What was this record breaking speed? 100 = 10.44 m/s 9.58

Calculating speed question A train takes 100 seconds to travel 1,500 m. What is the speed of the train? speed = distance time = 1,500 100 Photo credit: Jerry Pank = 15 m/s

Using a formula triangle A formula triangle helps you to rearrange a formula. The formula triangle for speed (s), distance (d) and time (t) is shown below. Cover the quantity that you are trying to work out, which gives the rearranged formula needed for the calculation. So to find speed (s), cover up s…  x …which gives the formula… s = d t

Calculating speed question A car travels at 25 m/s for 3 minutes. How far does it travel? speed = distance time distance = speed x time = 25 x 180 Photo credit: Crispin Proctor = 4,500 m = 4.5 km

What about velocity???

How is velocity different to speed? The speed of an object does not depend on the direction in which it is travelling. The velocity of an object is the speed and direction in which it is moving. The car is travelling north with a velocity of 10 m/s. As the car goes round the corner, the speed of the car remains constant but the velocity changes.

Speed or Velocity? A.35m/s B.35m/s North D. 2m/s SW C. 10km/h  E.

Why does direction matter?

Relative velocity Still water Against the current With the current

Relative Velocity Questions You can swim at 5m/s. How long does it take to swim across a swimming pool with a length of 25m? You now swim in a river with a current against you of 2m/s. What is your relative velocity in the river? How long does it take to swim 25m now? You turn round and swim back with the current. What is your relative velocity? How long does it take to swim back to your start point?

Where are you now? WWW………… EBF…………….. State what speed means Estimate some speed values Calculate speeds using formula Rearrange the formula to calculate time and distance. Describe the difference between speed and velocity. Calculate velocity when objects are moving relative to each other