Acceleration is the rate at which speed is changing over time. Looking at a speed vs time graph, we can see where acceleration is occurring. At the points where the graph is sloping there is acceleration or deceleration. If the graph slopes as shown between 0 and 20 seconds acceleration is taking place. If the slope is as shown between 30 and 33 seconds deceleration is taking place.

The steeper the slope the faster the speed is changing and therefore the greater the acceleration or deceleration.

If the graph is straight, speed is constant and therefore acceleration is 0. In other words no change in speed is taking place.

Answer TRUE or FALSE for the following statements.

a) During 0 and 20 seconds the rocket is not accelerating. True False

b) During 20 and 30 seconds there is a massive deceleration that stops the rocket from moving. True False

c) The deceleration between 30 and 33 is greater in magnitude than the acceleration between 0 and 20 seconds. True False

d) The rocket is decelerating slowly between 45 and 60 seconds True False

e) There is no acceleration between 33 and 45 seconds. True False