Don't ask the question, "Why can't time be negative?" Doing so seems to make the matter more interesting to many. Still, I know why I liked the first title. 🙄
Let me first clarify one thing - do all the t (time) quantities we use in physics really represent time?
The answer is, no.
In physics, time intervals are used in most places. Where I say t = 5 sec there is actually a time interval of 0 to 5 seconds.
Now the question is, "Where is the time used?" A simple answer - on the clock.
Now come to the topic .....
Madan Lal is a famous astrologer. He always leaves ahead of time. Looking at a person's hand for 2 seconds and filling his pocket with 2000 rupees can tell his future. However, before the customer tells his past story to Madan Lal, he knows everything. How do you know? It's a secret ...
Ordinary people are jealous of him for this. Maybe if we didn't write the word "since, time can't be negative, t = (-ve) inconsistent" in the test book, we would all become astrologers.

"How long will it take for an object to reach the x point if it is thrown upwards at a velocity u from a height h?" (See figure below)
. Now if we want to find the time elapsed at the point 'x', we will encounter a quadratic equation.
And if we solve it, we get two values ​​of t, one positive (+ ve) and the other negative (- ve). Although we were supposed to be amazed here, we were reminded that 'time cannot be negative', so we do not bother with negative values.
It is better to say one thing. Mathematics never comes up with fake solutions. If an equation (problem) is solved correctly by mathematics, all its possible answers will come out.
Well, what does t = (- ve) mean? Very short time? Bacteria size time? Or unrealistic time?
Nah. In fact, the mathematics here assumes that the object has gained velocity at a height as it rises at a certain speed. We assumed that the object was fixed at a height h and we threw it upwards at a velocity from there. But the math says, "No, he's never been static."
What is happening then? According to mathematics, once the object rises to a height h, it reaches the point x, the answer is negative. Once again the object will reach the point x as it descends, the answer is out as positive.
Similarly, if the question were, "How long will it take for the object to descend again 'from the ground to h height'?" Then we get two values ​​of t, t = 0 and t = (+ ve). Why? I won't say that again ...
Madan Lal's secret is no longer a secret. We can now find out the past events of others (even ourselves) if we want. Just waiting for the value of t to be placed negatively in the equation.
Summary: Time is negative, not again. Just depends on where we are using the time and time interval.
Phêñõmeñãl Omi‎