When an object moves in a straight line with uniform speed change, the velocity is 4m / s at a certain moment, and it becomes 10m / s after 1s? Let's first specify that the initial velocity direction is positive, then the velocity of 10m / s may be positive or negative If it is positive: a = 10-4 / 1 = 6m / S ^ 2 s = (4 + 10) * 1 / 2 = 7M If it is negative: a '= - 10-4 / 1 = - 14m / S ^ 2 s' = (4-10) * 1 / 2 = 3M Then the initial velocity direction should be negative, There are four answers? I thought about it for a long time

When an object moves in a straight line with uniform speed change, the velocity is 4m / s at a certain moment, and it becomes 10m / s after 1s? Let's first specify that the initial velocity direction is positive, then the velocity of 10m / s may be positive or negative If it is positive: a = 10-4 / 1 = 6m / S ^ 2 s = (4 + 10) * 1 / 2 = 7M If it is negative: a '= - 10-4 / 1 = - 14m / S ^ 2 s' = (4-10) * 1 / 2 = 3M Then the initial velocity direction should be negative, There are four answers? I thought about it for a long time

There are only two
The four you said think like this: if the initial velocity is positive, you get 6m / S ^ 2, - 14m / S ^ 2
When the initial velocity is negative, we get - 6m / S ^ 2,14m / S ^ 2
In fact, if the initial velocity is positive, we get 6m / S ^ 2 and negative initial velocity, we get - 6m / S ^ 2 is the same,
When the initial velocity is positive, 6m / S ^ 2 is obtained, which is in the same direction as the initial velocity,
When the initial velocity is negative, we get - 6m / S ^ 2, which means that it is opposite to the initial velocity, and the negative offset is the same