Distance, speed and acceleration Physics 2 Chapter 15 GCSE Additional Science

Distance, speed and acceleration V × t Speed = distance (metres) time (seconds) Click here for the answers Aled walks 200m in 40s. What is his speed? Lowri travels 2km in 1000s. What is her speed? How long would it take for Dafydd to run 100m if he runs at a speed of 10m/s? Heledd travels at a speed of 50m/s for 20s. How far does she travel? A car travels at a speed of 85 mph (about 40m/s). How long would it take for him to travel 20km? 1) 5m/s 2) 2m/s 3) 10s 4) 1000m/s 5) 500s Chapter 15 GCSE Additional Science

Distance-Time Graphs 40 30 20 10 GCSE Additional Science Chapter 15 4) Straight line at a downwards angle = 2) Straight horizontal line = 40 30 20 10 Motionless Constant speed in reverse 3) Straight line at a greater angle upwards = Distance (metres) Chapter 15 GCSE Additional Science Straight line at an upwards angle = Time/s 20 40 60 80 100 Constant speed forwards (high) Constant speed forwards (low)

GCSE Additional Science 40 30 20 10 Distance (m) 20 40 60 80 100 Time (s) Chapter 15 GCSE Additional Science What is the speed during the first 20s? How far is the object from the start after 60 seconds? What is the speed during the last 40s? When was the object travelling at its fastest? Click here for the answers 1) 0.5m/s 2) 40m 3) 2m/s in reverse 4) 40 – 60s

Speed v Velocity GCSE Additional Science Chapter 15 Simply, speed is the distance travelled per second … This car’s speed is 20m/s Velocity is the distance travelled per second in a specific direction ….. Chapter 15 GCSE Additional Science Speed of 20m/s to the right

Acceleration change in velocity (m/s) acceleration (m/s2) = time (s) V - U a × t A biker speeds up from 0 to 10m/s in 5 s. What is the acceleration? A ball is dropped with an acceleration of 10m/s2 for 12s. By how much will the velocity of the ball change? A car speeds up from 10 to 20m/s with an acceleration of 2m/s2. How much time did this change take? A rocket speeds up from 1 000m/s to 5 000m/s in 2s. What is its velocity? Click here for the answers Chapter 15 1) 2m/s2 2) 120m/s 3) 5s 4) 2000m/s2 GCSE Additional Science

Constant deceleration Constant acceleration (lower) Velocity-Time Graphs Line at an upwards angle = 80 60 40 20 Constant acceleration 4) Line at a downwards angle = Constant deceleration 3) Line at an upwards angle = velocity (m/s) 2) Horizontal line = Chapter 15 GCSE Additional Science t(s) 10 20 30 40 50 Constant velocity Constant acceleration (lower)

Calculating the Distance 80 60 40 20 Velocity (m/s) t/s Chapter 15 GCSE Additional Science 10 20 30 40 50 To calculate the total distance of the journey, you must calculate the area under the graph.

GCSE Additional Science 80 60 40 20 Velocity (m/s) t/s 10 20 30 40 50 Chapter 15 What is the velocity after 10s? What is the acceleration between 20 a 30s? What is the deceleration between 30 and 50s? What was the distance of the journey? Click here for the answers GCSE Additional Science 1) 40m/s 2) 2m/s2 3) 3m/s2 4) 1700m