Motion in Two Dimensions-Projectile off cliff

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In summary, the conversation discusses a problem involving a student throwing a stone from a cliff with a given initial speed and height. The coordinates and initial velocity components are determined, and equations for the velocity and position of the stone with time are requested. The time it takes for the stone to hit the beach below the cliff, as well as its speed and angle of impact, are also asked for. The equations of motion in the x and y directions are suggested for parts c and d, and finding the final velocity in both directions and using trigonometry to solve for the angle is recommended for part f.
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Originallist
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Homework Statement


A student stands at the edge if a cliff and throws a stone horizontally over the edge with a speed of 18.0m/s. The cliff is 50.0m above a flat, horizontal beach.
a.) What are the coordinates of the initial position?
b.)What are the components of the initial velocity?
c.) Write the equations for the x- and y- components of the velocity of the stoned with time.
d.) Write the equations for the position of the stone with time, using coordinates.
e.) How long after being released does the stone strike the beach below the cliff?
f.) With what speed and angle of impact does the stone land?


Homework Equations


I understand some, but am getting confused with the individual components of x and y.


The Attempt at a Solution


We were given a picture (attached)
for a.) I decided to let the point where the rock would start at to be the origin (0,0).

for b.) I knew the x component=18.0 m/s and y= 0m/s at the start.

I know gravity= -9.8m/s and my Dvertical=-50 m. I also know that ViVertical=0m/s...

for e.) I was able to find the time by using Dvertical=Vivertical(t)+(1/2)gt^2... I got t as 3.19 seconds.

What do I do for c, d, and f though? Any help would be tremendous!
 

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  • #2
For c. use an equation of motion in the y direction ans use an equation of motion in the x direction.
You will have different initial velocity values etc..For d, key words.
Equation, position (displacement), time.
Do you know of any equation like this? For F, find the final velocity of the stone, in both X & Y directions. You will then have something like (aX - bY)
You can then use trigonometery to solve the angle.
 
  • #3
I note that the attached image indicates an origin for the coordinate system at the base of the cliff (the "O" mark). You might want to consider if this will make a difference for your answer submission.
 

1. What is the formula for calculating the horizontal distance of a projectile off a cliff?

The formula for calculating the horizontal distance of a projectile off a cliff is x = v0 * t, where x represents the distance, v0 represents the initial velocity, and t represents the time.

2. How does the angle of projection affect the range of a projectile off a cliff?

The angle of projection affects the range of a projectile off a cliff by determining the vertical and horizontal components of the initial velocity. A larger angle will result in a greater vertical component and a shorter horizontal component, leading to a shorter range. A smaller angle will result in a smaller vertical component and a longer horizontal component, leading to a longer range.

3. What is the maximum height reached by a projectile off a cliff?

The maximum height reached by a projectile off a cliff can be calculated using the formula y = (v0)2sin2θ / 2g, where y represents the maximum height, v0 represents the initial velocity, θ represents the angle of projection, and g represents the acceleration due to gravity.

4. How does air resistance affect the motion of a projectile off a cliff?

Air resistance can affect the motion of a projectile off a cliff by slowing it down and altering its trajectory. This can result in a shorter distance traveled and a different maximum height reached compared to a projectile without air resistance. The effect of air resistance is more significant for objects with a larger surface area and lower mass.

5. How does the mass of a projectile affect its motion off a cliff?

The mass of a projectile does not affect its motion off a cliff, as long as air resistance and other external forces are ignored. This is because the acceleration due to gravity is constant for all objects, regardless of their mass. However, in real-world situations, air resistance and other external factors can have a greater impact on objects with a larger mass.

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