Yahoo Answers is shutting down on May 4th, 2021 (Eastern Time) and beginning April 20th, 2021 (Eastern Time) the Yahoo Answers website will be in read-only mode. There will be no changes to other Yahoo properties or services, or your Yahoo account. You can find more information about the Yahoo Answers shutdown and how to download your data on this help page.
Trending News
ball thrown vertically upwards physics?
a ball thrown vertically upwards from a bridge that is 40m above ground. The ball strikes ground in 4 seconds. What is speed at which ball was thrown upwards, and at what speed will ball hit ground?
Iv been stuck for a long time please any help will help.
2 Answers
- Big DaddyLv 710 years agoFavorite Answer
With the displacement formula (x = v0 *t + (1/2) a t^2), you have all the values except the unknown initial velocity. So solve for that.
x = v0 t + (1/2) a t^2
v0 t = x - (1/2) a t^2
v0 = (x - .5 a t^2) / t
v0 = (40m - .5 (9.81m/s^2) (4s)^2) / 4s
v0 = (40m - .5 (9.81 m/s^2) (16s^2)) / 4s
v0 = (40m - 78.5m) / 4s
v0 = -38.5m / 4s
v0 = -9.6 m/s
Since gravitational acceleration is downward (and positive), the negative initial velocity implies an upward direction.
v = v0 + a t
v = -9.6m/s + 9.81m/s^2 * 4s
v = -9.6m/s + 39.24 m/s
v = 29.6 m/s
- jimmymae2000Lv 710 years ago
1/2 A T^2 = distance, so 3 sec = 45 m &(30 m/s) down, up at 10m/s should stop in one meter with 5 meter displ.