10.1 Measuring speed

10.1 Measuring speed

Objectives:

• Define Speed

• Measure average speed

• Identify movement

Multiple Choice

What was the speed limit in wet weather?

• 130 km/hr

• 110 km/hr

• 120 km/hr

• 115 k/hr

Open Ended

In stage 7, you learnt about forces and motion. Use what you learnt to explain why cars should travel more slowly in wet weather?

Speed

• Some vehicles move faster than the others. They have different speed

• Speed is the quantity that tells us how fast something is moving.

• Example: The car's speed was 50 kilometers per hour when it hit the wall.

• Remember: When we give measurement, we give its value including the unit.

Open Ended

A speed of 50km/hr. What does that mean?

How can we measure a runner's speed?

• We need to find how many meters a runner travels in each second.

• There are 2 quantities to be measured: distance travelled (in meters, m)

• time take (in seconds, s)

• Formula: Average speed= distance travelled/time taken

Multiple Choice

The distance travelled is 200m and the time take is 25s. So:

• 8m/s

• 10m/s

• 12m/s

• 5m/s

Open Ended

A car travels 100m in 5s. What is the average speed?

Multiple Choice

A red car travels 400m in 20s. A blue car travels 660m in 30s. Which car has the greater average speed?

• red car:

• blue car