# Balls dropped and thrown at the same time

• wmsaqqa
In summary, the conversation discusses two scenarios where a ball is thrown up from the edge of a building and a second ball is dropped from the roof. The question is asked about the initial speed and height of the building for both balls to hit the ground at the same time. Using the formula y = v0t - 1/2gt^2, the initial speed for the first ball is calculated to be -22.5 for the first scenario and the height of the building for the second scenario is calculated to be -3.66. However, the answers are incorrect and further assistance is needed.
wmsaqqa
A ball is thrown straight up from the edge of the roof of a building. A second ball is dropped from the roof a time of 1.14 later. You may ignore air resistance.A- If the height of the building is 19.3 , what must the initial speed be of the first ball if both are to hit the ground at the same time?B- Consider the same situation, but now let the initial speed of the first ball be given and treat the height of the building as an unknown. What must the height of the building be for both balls to reach the ground at the same time for v0 = 8.80 .

i need a help for this question please.. 3 hours and I am getting a wrong answers..

i used these formulas : y=v0.t-1/2.g.t2 , and this : y=1/2.(v0-v).t

Last edited:

It would help if you showed what you have done. Yes, y= v_0t- (1/2)gt^2 will help here. The second ball is dropped- i.e. has v_0= 0. So when will that ball hit the ground? Set t equal to that for the first ball and solve for v_0.

for A .. i got this answer : -22.5
right?

Last edited:

for B.. i got the answer -3.66

and both the answers are wrong.. !

HallsofIvy said:
It would help if you showed what you have done. Yes, y= v_0t- (1/2)gt^2 will help here. The second ball is dropped- i.e. has v_0= 0. So when will that ball hit the ground? Set t equal to that for the first ball and solve for v_0.

I need a help and check for my answers.. and i showed you the formula and you said that this formula is right.. but the answers are wrong..

## 1. How does gravity affect balls dropped and thrown at the same time?

Gravity affects all objects, including balls, in the same way. When a ball is dropped or thrown, it will accelerate towards the ground at a rate of 9.8 meters per second squared due to the force of gravity.

## 2. Will the balls hit the ground at the same time?

Yes, if the balls are dropped and thrown at the same time and from the same height, they will hit the ground at the same time. This is because both balls are experiencing the same acceleration from gravity.

## 3. What factors can affect the time it takes for the balls to hit the ground?

The main factor that can affect the time it takes for the balls to hit the ground is air resistance. If one of the balls has a larger surface area or is shaped differently, it will experience more air resistance and therefore take longer to reach the ground.

## 4. Can the speed of the thrown ball affect the time it takes for it to hit the ground?

Yes, the speed of the thrown ball will affect the time it takes for it to hit the ground. The ball with a greater initial velocity will travel a greater distance before reaching the ground, and therefore take longer to hit the ground.

## 5. What would happen if the balls were dropped and thrown on the moon?

If the balls were dropped and thrown on the moon, they would both hit the ground at the same time, just like on Earth. However, due to the lower gravity on the moon, the acceleration towards the ground would be much slower (around 1.6 meters per second squared), causing the balls to take longer to hit the ground compared to on Earth.

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