Question

A car start from rest and accelerates at the rate of 2m/s² for 5 seconds. it maintenance this velocity for another 5 seconds. it eventually undergoes a uniform deceleration and finally comes to rest after further 5 seconds.

A) draw the velocity-time graph for the journey

B) find the acceleration and deceleration respectively,

C) find the total distance travelled during each stage.

D) find the average velocity over the entire period ​

Answer 1

2m/s² ; - 2m/s²

25m ; 50m ; 25m

6.67 m/s²

Explanation:

The acceleration and deceleration :

Both rates are the Same from the graph ;

According to scenario described, acceleration = 2m/s²

Deceleration occurred in equal time interval = - 2m/s

Distance covered during each stage:

Stage 1 : area of triangle

0.5 * base * height

0.5 * 5 * 10 =25 m

Stage 2: area of rectangle :

Length * breadth = 5 * 10 = 50 m

Stage 3 : area of triangle

0.5 * base * height

0.5 * 5 * 10 =25 m

Average Velocity :

Total distance / time = (25 + 50 + 25) / 15 = 100/ 15 = 6. 67 m/s