Launch angle and Projectiles

In summary, the problem presents a scenario where two children are trying to play catch with a wall standing between them. The task is to determine the launch angle (theta) from the horizontal that the thrower must use to just clear the wall and still land at the catcher. The vertical and horizontal positions of the ball as functions of time are also to be determined. Using the given hints and equations, the attempt at a solution begins with drawing a diagram and using the equations to find the required functions. The final step involves finding the value of theta that grazes the wall.
  • #1
ScullyX51
36
0

Homework Statement


Suppose a very narrow, very tall wall of height H stands between two children who are trying to play catch. The wall is a distance x[wall] from the thrower, and the catcher is distance X[F] from the thrower. In this problem you will calculate the lunch angle (theta) from the horizontal that the thrower must use to just clear the wall and still land at the catcher. You may neglect the height of the children and the width of the wall.
a)Draw a diagram of the problem. (hint: do not assume that the wall's position is halfway between, or that the ball's peak height occurs at the wall)
b0 What is the vertical position of the ball (as a function of time), expressed in terms of the V[0] and the launch angle (theta)?
c) What is the horizontal position of the ball (as a function of time)?

Homework Equations


(delta)y= V[0]yt + .5agt^2
(delta)x= V[0]xt
Vyi= Vsin(theta)
Vxi=Vcos(theta)


The Attempt at a Solution


On the drawing the diagram part I am very confused. I don't know where to begin drawing, if have go by the given hints!

For part B: (the vertical position of the ball as function of time.)
y(t)= V[0]sin(theta)- gt^2/2
I do not think this is right because the problem specifies that the function should only be in terms of theta and v[0]. I do not know how to get this function without g!

For part C: i got the horizontal position of the ball to ne:
x(t)= V[0]cos(theta)t
 
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  • #2
ScullyX51 said:
For part B: (the vertical position of the ball as function of time.)
y(t)= V[0]sin(theta)- gt^2/2
I do not think this is right because the problem specifies that the function should only be in terms of theta and v[0]. I do not know how to get this function without g!

For part C: i got the horizontal position of the ball to ne:
x(t)= V[0]cos(theta)t


Hi ScullyX51! :smile:

(have a theta: θ and a squared: ² :smile:)

Your answers are fine.

You are always allowed to use g ! :biggrin:

To continue, first ignore the wall and find what v0 must be for each θ so as to land at the catcher.

Then find out which value of θ grazes the wall. :wink:
 
  • #3

This is correct, as it only depends on the initial velocity and launch angle, not the acceleration due to gravity.

I would like to clarify a few things about launch angle and projectiles.

Firstly, the launch angle is the angle at which an object is projected into the air. It is measured from the horizontal and can greatly affect the trajectory of the object.

In this particular problem, the launch angle must be calculated in order for the ball to clear the wall and reach the catcher. This can be done by using the equations for projectile motion, as shown in the attempt at a solution.

However, it is important to note that in real life situations, the height and width of the wall, as well as air resistance, would also affect the trajectory of the object and must be taken into account. This problem assumes ideal conditions, but in reality, these factors would need to be considered to accurately determine the launch angle.

Furthermore, the launch angle is not the only factor that affects the trajectory of a projectile. The initial velocity, air resistance, and the mass of the object also play a role.

In conclusion, while the launch angle is an important factor in determining the trajectory of a projectile, it is not the only factor and must be considered in conjunction with other factors to accurately predict the motion of an object.
 

1. What is launch angle and how does it affect projectiles?

Launch angle is the angle at which a projectile is launched into the air. It directly affects the trajectory and distance of the projectile. A higher launch angle will result in a higher trajectory and longer distance, while a lower launch angle will result in a shorter distance.

2. How can launch angle be calculated?

Launch angle can be calculated using trigonometry. The formula is: launch angle = arcsin (vertical velocity / initial velocity). This can also be calculated using a projectile motion calculator or with the use of a protractor and measuring the angle of the launch surface.

3. What is the optimal launch angle for maximum range?

The optimal launch angle for maximum range depends on the initial velocity of the projectile. For a given initial velocity, the optimal launch angle is 45 degrees. However, if the initial velocity is different, the optimal launch angle will also change. For example, if the initial velocity is lower, the optimal launch angle will be higher than 45 degrees.

4. How does air resistance affect the launch angle of a projectile?

Air resistance can affect the launch angle of a projectile by decreasing its initial velocity. This means that a higher launch angle is needed to achieve the same distance as a projectile launched without air resistance. Additionally, air resistance can cause the projectile to deviate from its intended trajectory, making it harder to accurately predict its landing point.

5. What are some real-life applications of understanding launch angle and projectiles?

Understanding launch angle and projectiles is crucial in various fields such as sports (e.g. basketball, baseball), military (e.g. missile launch), and engineering (e.g. launching satellites into orbit). It is also important in everyday activities such as throwing a ball or shooting a projectile with a slingshot.

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