# Physics

A ball is thrown horizontally from the roof of a building 9.0 m tall and lands 8.5 m from the base. What was the ball's intial speed?

I have no idea how to do this problemm or what formulas to use because of the fact that I do not know the time interval it took to fall. Sense it's asking for the intial speed it implies that there was one. Also does one need to find the inital speed in both the y axes and x axes?

1. 👍 0
2. 👎 0
3. 👁 839
1. I can offer a suggestion to get you started. The time is the easiest part of the problem to solve because the initial speed of the ball controls ONLY how far away from the base it falls. It does not control the time it takes to fall to the ground. distance = 1/2(g)t^2 where the distance the ball falls is 9 m. Solve for t.

1. 👍 0
2. 👎 0
2. The ball is thrown horizontally, so there is only an initial x velocity. You can find the time interval as shown below.

Start by finding the time the ball is in the air.

d = Vi(t) + 0.5(a)(t^2)

Acceleration is due to gravity. Initial velocity in the y direction is 0 because the ball is thrown horizontally.

9 = 0.5(-9.81)(t^2)
t = 1.355s

Now use V = d/t to find the horizontal velocity.

V = d/t
V = 8.5/1.355
V = 6.3m/s in the x direction

1. 👍 1
2. 👎 0
3. thanks a bunch I guess i didn't see the importance of the word horizontal

THANKS!!

1. 👍 0
2. 👎 0

## Similar Questions

1. ### science

Two stones are launched from the top of a tall building. One stone is thrown in a direction 30.0degree above the horizontal with a speed of 10.0m/s ; the other is thrown in a direction 30.0degree below the horizontal with the same

2. ### Physics

A ball is thrown horizontally at 12.2 m/s from the roof of a building and lands 21.0 m from the base of the building. How high is the building?

3. ### Physics

A target lies flat on the ground 4 m from the side of a building that is 10 m tall, as shown below. The acceleration of gravity is 10 m/s2 . Air resistance is negligible. A student rolls a 4 kg ball off the horizontal roof of the

4. ### Physics

You are walking around your neighborhood and you see a child on top of a roof of a building kick a soccer ball. The soccer ball is kicked at 41° from the edge of the building with an initial velocity of 21 m/s and lands 59 meters

1. ### physics

A ball thrown horizontally at 13.0m/s from the roof of a building lands 21.4m from the base of the building. How tall is the building?

2. ### Science

A ball is thrown horizontally from the roof of building 50.m tall and lands 45m from the base. What was the balls initial speed

3. ### Physics

A ball is thrown horizontally from the roof of a building 45cm tall and lands 24.0m from the base. What was the ball's initial velocity?

4. ### Physics

A ball is thrown horizontally from the top of a building. The ball is thrown with a horizontal speed of 8.2 ms^-1. The side of the building is vertical. At point P on the path of the ball, the ball is distance x from the building

1. ### physical

baseball is hit with a speed of 30.0 m/s at an angle of 50 It lands on the flat roof of a 10m tall nearby building, If the ball was hit when it was 1.5 m above the ground, what horizontal distance does it travel before it lands on

2. ### Physics

A rock is thrown directly upward from the edge of the roof of a building that is 40.2 meters tall. The rock misses the building on its way down, and is observed to strike the ground 4.00 seconds after being thrown. Neglect any

3. ### Physics

A baseball is hit with a speed of 27.0 m/s at an angle of 42.0 deg. It lands on the flat roof of a 10.0 m-tall nearby building. If the ball was hit when it was 1.0 m above the ground, what horizontal distance does it travel before

4. ### Physics

Stones are thrown horizontally with the same velocity from the tops of two different buildings. One stone lands twice as far from the base of the building from which it was thrown as does the other stone. Find the ratio of the