When an object moves in a variable speed linear motion, the velocity is 4 m / s at a certain moment, and becomes 10 m / s after 2 seconds, then the average acceleration of the object in these 2 seconds is less than 10 m / s? Why? I know the answer 3m / S2 and 7m / s2

When an object moves in a variable speed linear motion, the velocity is 4 m / s at a certain moment, and becomes 10 m / s after 2 seconds, then the average acceleration of the object in these 2 seconds is less than 10 m / s? Why? I know the answer 3m / S2 and 7m / s2

Take the velocity direction of "the velocity is 4m / s at a certain time" as the positive direction, that is, V0 = 4m / St = 2 seconds. Analysis: when the direction of the final velocity is the same as the direction of the initial velocity, v = 10m / S (take as a positive value) in this case, the average acceleration is a = (v-v0) / T = (10-4) / 2 = 3 M / S ^ 2