Question

Using the following velocity time graph of a body answer the following questions.
1. During which time intervals is the body moving with variable velocity?
2. What is the acceleration of the body during the intervel 3 sec to 5 sec ?
3. What is the displacement of the body in the last four seconds of its motion ?​

Answer 1

Answer:

Explanation:1.) 3seconds to 5 seconds

2.) Zero

3.) O-15/4= -3.75

Answer 2

Answer to the above question using the provided graph is:

(a) The body is moving with variable velocity during the intervals of 0 to 3 seconds and 5 to 7 seconds as the graph is having a slope and not a line parallel to y axis.

(b) Since acceleration is defined as the rate of change of velocity therefore between time interval of 3 to 5 seconds the velocity is constant and hence zero acceleration.

(c) For displacement in last four seconds the displacement is given by the area under the graph. You can see it consists of two parts:

rectangular part (from 3 to 5 seconds): Area = 2 x 15 = 30 m

Triangular part (from 5 to 7 seconds): Area = $\frac{1}{2}$ x 2 x 15 = 15 m

Total area = 30 + 15 = 45 m

Hence displacement is 45 m in last 4 seconds