# Solving a Ball Thrown off a Cliff: How Long Does it Take?

• NotInMrPutmansClass
In summary, the ball takes 2.7584 seconds to strike the ground and the height of the cliff cannot be determined based on the given information.
NotInMrPutmansClass
Homework Statement
Find the height of a cliff using a ball thrown at an angle and find how long it takes the ball to hit the ground.
Relevant Equations
a-sinA, aCosA
This is the question:
A ball is thrown with a speed of 6m/s at an angle of 25° above the horizontal from the top of a cliff. The ball strikes the ground 15 m from the bottom of the cliff.

How long does it take the ball to strike the ground?

How long is the cliff?Here's a visual representation of the problem.

I broke the angle into vectors

I solved for the time of the ball in the
x-axis

t=d/v
t=15m / 5.4378m/s
t = 2.7584 Seconds

But now I'm stuck and I'm lost on what to do next

Last edited:
Welcome to PF.

I'm not able to see much in your attached images -- I seem to only be seeing thumbnail-size images and they are not well lit. Could you maybe use a printer/scanner to generate better copies?

NotInMrPutmansClass said:
But now I'm stuck and I'm lost on what to do next
After you post legible figures, you should write the appropriate equation(s) for the motion in the vertical direction.

berkeman said:
Welcome to PF.

I'm not able to see much in your attached images -- I seem to only be seeing thumbnail-size images and they are not well lit. Could you maybe use a printer/scanner to generate better copies?
I reposted the pictures and they seem to be fine now.

NotInMrPutmansClass said:
I reposted the pictures and they seem to be fine now.
What's the problem with getting the height of the cliff, now you have the time of flight?

## 1. How is the time taken for a ball thrown off a cliff calculated?

The time taken for a ball thrown off a cliff can be calculated using the equation t = √(2h/g), where t is the time in seconds, h is the height of the cliff in meters, and g is the acceleration due to gravity (9.8 m/s²).

## 2. Does the mass of the ball affect the time taken?

No, the mass of the ball does not affect the time taken for it to reach the ground. This is because the acceleration due to gravity is constant for all objects, regardless of their mass.

## 3. Is air resistance taken into account when calculating the time taken?

In most cases, air resistance is neglected when calculating the time taken for a ball thrown off a cliff. This is because air resistance only has a significant effect on the motion of objects with a large surface area, such as parachutes or feathers.

## 4. How does the angle at which the ball is thrown affect the time taken?

The angle at which the ball is thrown does not affect the time taken for it to reach the ground, as long as the initial velocity and height of the cliff remain the same. This is because the time taken is only dependent on the height and acceleration due to gravity.

## 5. Can the time taken be affected by external factors?

Yes, the time taken for a ball thrown off a cliff can be affected by external factors such as wind or air resistance. These factors can alter the trajectory of the ball and therefore affect the time taken for it to reach the ground.

• Introductory Physics Homework Help
Replies
14
Views
1K
• Introductory Physics Homework Help
Replies
8
Views
5K
• Introductory Physics Homework Help
Replies
6
Views
957
• Introductory Physics Homework Help
Replies
8
Views
3K
• Introductory Physics Homework Help
Replies
7
Views
2K
• Introductory Physics Homework Help
Replies
5
Views
5K
• Introductory Physics Homework Help
Replies
1
Views
1K
• Introductory Physics Homework Help
Replies
2
Views
3K
• Introductory Physics Homework Help
Replies
4
Views
1K
• Introductory Physics Homework Help
Replies
9
Views
2K