A ball is thrown verticaly from the ground .Find out the time and velocity when the ball reach 10 and 40m from the ground. The time given between 10m and 40m is 4s. I tried to solve this question by asumming that t30 = t10 + 4s and I found that the value of v30 is negative. So I try another way to solve it. This time I do not assume t30 = t10 + 4s. I find out all the values besides t first and finally I got the value of v30 is positive . However, t30 is not equal to t10 + 4s . :grumpy: :grumpy: :grumpy: What`s wrong actually??