Question

The velocity time graph of a car shown below a) Calculate the magnitude of displacement of the car in 40 seconds. b) During which part of the journey was the car accelerating? c) Calculate the magnitude of average velocity of the car.

Answer 1

Answer:

a) 600 meters b) During OA, AB c) 15m/s

Explanation:

Displacement can be taken out as by using equations or by taking out the areas of triangles and the rectangle. Average velocity = Total displacement/ Total time. We know the time and displacement as we took out. As we can see body accelerating during OA and AB

Answer 2

Answer:

a) Magnitude of displacement =  600m

b) From O to A

c) 15m/s

Explanation:

a) It is known that the magnitude of displacement is distance, which is the scalar quantity of displacement.

Therefore, distance = Area under the graph of velocity-time graph

Distance= $\frac{1}{2}$ ( sum of parallel sides) *height

= $\frac{1}{2}$ ( 40 + (30 - 10)) *20= 600m

b) Acceleration depends on the gradient of the velocity-time graph because it is the ratio of velocity and time ($gradient = \frac{v}{t}$) . So when the gradient is positive, the car is accelerating, which is seen between A and O.

c) Magnitude of average velocity is basically the average speed,

therefore,

Average speed = ( Total distance travelled / Total time taken to travel )

= (600) / (40) = 15m/s