A ball is thrown upwards with a velocity of 100 m/s. When will it reach the ground?
There is a simple formula one can use to solve these kind of problems that the other answers actually used to solve this problem. Here it is :Vf = Vi + a*tTo find the final velocity, you need the initial velocity and add the acceleration multiplied with time.In your problem (say the ball is leaving from the ground), your initial velocity (Vi) is 100 m/s and at the highest point, the velocity (Vf) is zero. Gravity is always 9.8m/s squared. The only variable missing is time. Let’s solve our equation. (the gravity is negative because it slows down our velocity)0 = 100 + (-9.8)*t → t=100/9.8 = 10.20 secondsSince we only calculated our ball going up, we multiply it by two to get the up and down value of 20.4 seconds. (You can do the same calculations with Vi=0m/s, Vf=100m/s and a=9.8m/s(squared) but you will find the exact same answer of 10.2.)There you go! Now you can use this new formula to solve similar problems with different values!