Projectile motion- Deriving the right formular

[majormuss]

Homework Statement

Projectile A is launched horizontally at a
speed of 20. meters per second from the top of
a cliff and strikes a level surface below, 3.0 seconds
later. Projectile B is launched horizontally
from the same location at a speed of 30. meters
per second.
Approximately how high is the cliff?
(1) 29 m (3) 60. m
(2) 44 m (4) 104 m

Homework Equations

d=tv

The Attempt at a Solution

On two occasions my answer turn out to be '3' and '4'. but the answer key says it's '2'. I have tried for hours but i can't find the right approach. Please offer me a good explanation of how I should work with this? or u can even give me a link to read more or something.

 

[rl.bhat]

Use the equation
h = 1/2*g*t^2

 

[kerimek]

As a scientist, it is important to approach problems with a systematic and logical mindset. In this case, we can use the equation d=tv to solve for the height of the cliff.

First, let's define our variables. d represents the distance, t represents time, and v represents velocity (speed).

We are given the velocity of projectile A (20 m/s) and the time it takes to reach the surface below (3.0 seconds). Using the equation d=tv, we can rearrange it to solve for d, which represents the height of the cliff.

d = tv
d = (20 m/s)(3.0 s)
d = 60 m

Therefore, the height of the cliff is approximately 60 meters. This aligns with answer choice (3) in the homework statement.

For projectile B, we are given a different velocity (30 m/s) but we can use the same equation to solve for the height of the cliff.

d = tv
d = (30 m/s)(3.0 s)
d = 90 m

This means that if projectile B was launched horizontally at 30 m/s, it would reach a height of 90 meters before hitting the surface below. This aligns with answer choice (2) in the homework statement.

In summary, the key to solving this problem is to use the given information and the appropriate equation to solve for the unknown variable (in this case, the height of the cliff). It is important to carefully define your variables and units and to double check your calculations to ensure accuracy. I hope this explanation helps you understand the concept of projectile motion and the use of equations in problem-solving. You can also find more resources and practice problems online to further enhance your understanding.