The displacement of a particle in the first △ t time is S1, and the displacement in the second △ t time is S2. Calculate the average velocity and the instantaneous velocity in the middle time The displacement of a particle is S1 in the first △ t time and S2 in the second △ t time The average speed in these two periods___________ The instantaneous velocity at the middle of the two periods______________

The displacement of a particle in the first △ t time is S1, and the displacement in the second △ t time is S2. Calculate the average velocity and the instantaneous velocity in the middle time The displacement of a particle is S1 in the first △ t time and S2 in the second △ t time The average speed in these two periods___________ The instantaneous velocity at the middle of the two periods______________

According to the concept of average velocity: the total displacement is greater than the total time, the total displacement in these two periods is (S1 + S2), and the total time is (2 △ T),
So: the average velocity is (S1 + S2) / (2 △ T)
According to the law of uniform variable speed linear motion, "the instantaneous velocity in the middle time is equal to the average velocity in this period of time."
So: the instantaneous velocity in the middle is (S1 + S2) / (2 △ T)