In the first 10 seconds, the object moves forward 10 meters 1. What are the displacements in the last 10 seconds and the 10th? 2. What is the average velocity in the first six seconds and the sixth?

In the first 10 seconds, the object moves forward 10 meters 1. What are the displacements in the last 10 seconds and the 10th? 2. What is the average velocity in the first six seconds and the sixth?

(1) Solution 1 is obtained from the displacement formula of uniformly accelerating linear motion with zero initial velocity
s=at^2/2
a=2s/t^2=0.2m/s^2
The displacement in the last 10 seconds is 0
s'=at'^2/2-at^2/2=0.2/2(20^2-10^2)m=30m
Solution 2. The displacement ratio of uniformly accelerating linear motion with zero initial velocity in continuous equal time is
1：3：5.
So s': S = 3:1
s'=3s=30m
The displacement within 10s is (note that 10s is the tenth 1s)
s"=a/2*(10^2-9^2)=1.9m
(2) The displacement of the first 6 s is 0
s6=0.2*6^2/2m=3.6m
The average speed is V6 = S6 / T = 3.6 / 6m / S = 0.6m/s
The displacement of 6S is S6 '= A / 2 * (6 ^ 2-5 ^ 2) = 1.1m
The average velocity is V6 '= S6' / T = 1.1 / 1m / S = 1.1m/s