Projectile Motion Analyzation Problem

In summary, the conversation discusses the problem of a cannonball being fired from a cannon at 45 m/s at an angle theta towards a car that is moving at a constant speed of 20 m/s. The question is at what distance the cannonball will hit the car. The attempt at a solution involves using the range formula, but it is impossible to solve with the given information. The conversation also mentions the possibility of selecting an angle to give the maximum range of the cannonball and questions whether the cannonball can reach the car if it is moving. It also raises the issue of dealing with the variables of theta and time with the only given relation. Finally, it is suggested to use the range formula with the angle for maximum range to
  • #1
Not a Wrench
22
1

Homework Statement


A cannonball is fired out of a cannon at 45 m/s at an angle theta in the positive x direction 500 meters away from a car moving in the positive x at a constant 20 m/s. At what distance does the cannonball hit the car?

Homework Equations


I am unsure of how I would solve theta.

The Attempt at a Solution


O= theta
I tried to use the range formula: d=V^2/g * sin(2O)
So I plugged in all the numbers and it's impossible to do that. sin(2O)=2.42 which is impossible. Is it impossible to figure this out if just given the Vo?
 
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  • #2
Not a Wrench said:

Homework Statement


A cannonball is fired out of a cannon at 45 m/s at an angle theta in the positive x direction 500 meters away from a car moving in the positive x at a constant 20 m/s. At what distance does the cannonball hit the car?

Homework Equations


I am unsure of how I would solve theta.

The Attempt at a Solution


O= theta
I tried to use the range formula: d=V^2/g * sin(2O)
So I plugged in all the numbers and it's impossible to do that. sin(2O)=2.42 which is impossible. Is it impossible to figure this out if just given the Vo?
You should be able to select θ to give the maximum range of the cannonball when it is fired at 45 m/s.

At this maximum range, is the cannonball capable of reaching the car, assuming the car is 500 m from the cannon and the car is stopped?

What will change if the car starts moving just as the cannon is shot?

What can you conclude about the speed of the cannonball as it leaves the cannon?
 
  • #3
The distance that the ball runs finally, that is, your ##d,## should be equal to the original distance the car from you and the distance it makes during the time, which may be what you miss.
But I'm also not sure how to deal with these 2 variables ##\theta## and ##t## with the only relation...
 
  • #4
tommyxu3 said:
The distance that the ball runs finally, that is, your ##d,## should be equal to the original distance the car from you and the distance it makes during the time, which may be what you miss.
But I'm also not sure how to deal with these 2 variables ##\theta## and ##t## with the only relation...
You should not assume automatically that a cannonball fired with an initial velocity of 45 m/s will be able to cover 500 m.

That's why I suggested that the range formula should be used in conjunction with the angle which gives the maximum range to see if the cannonball is in fact capable of reaching 500 m. The answer may surprise you.
 

1. What is projectile motion?

Projectile motion is the motion of an object that is launched or thrown and moves through the air under the influence of gravity alone. This type of motion follows a curved path known as a parabola.

2. How is the trajectory of a projectile calculated?

The trajectory of a projectile is calculated using the equations of motion, which take into account the initial velocity, angle of launch, and acceleration due to gravity. These equations can be solved using algebra or with the help of computer software.

3. What factors affect the trajectory of a projectile?

The trajectory of a projectile is affected by the initial velocity, angle of launch, and acceleration due to gravity. Other factors that may affect it include air resistance, wind, and the shape of the object.

4. How is the range of a projectile determined?

The range of a projectile is determined by the horizontal distance it travels before hitting the ground. It is dependent on the initial velocity and angle of launch, and can be calculated using the formula: range = (initial velocity squared x sine(2 x launch angle)) / acceleration due to gravity.

5. How is projectile motion used in real life?

Projectile motion is used in real life in various applications such as sports, military, and engineering. Examples include throwing a ball, shooting a cannon, and launching a rocket. It is also used in ballistics to predict the trajectory of a bullet or missile.

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