The velocity-time plot for a particle
moving on a straight line is
A) The particle has a constant
acceleration.
B) The particle has never turned around.
C) The particle has zero displacement.
D) The average speed in the interval o to
10 s is the same as the average speed in
the interval 10 s to 20 s.
Choose correct options.
Answers
Answer
(a) The particle has a constant acceleration.
(d) The average speed in the interval 0 to 10 s is the same as the average speed in the interval 10 s to 20 s.
Explanation:
(a) is true because in a velocity time graph the slope (which shows rate of change of velocity) denotes acceleration. In this graph the slope is constant, so acceleration is constant.
(b) is not true because at t=10 s the velocity changes its sign from positive to negative, means it has turned around.
(c) is not true because displacement in the positive direction of v is given by the area of graph above the time axis and displacement in the negative direction of v is given by area of the graph below the time axis. In this case later is greater than former not equal. So displacement is not zero.
(d) is true because in 0 to 10 s speed changes from 10 to 0 m/s and in 10 to 20 s speed changes from 0 to 10 m/s. So average speed will be the same.