Projectile Motion Analyzation Problem

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Homework Help Overview

The problem involves a cannonball being fired at a specific speed and angle towards a moving car, with the goal of determining the distance at which the cannonball will hit the car. The subject area includes projectile motion and kinematics.

Discussion Character

  • Exploratory, Assumption checking, Problem interpretation

Approaches and Questions Raised

  • Participants discuss the use of the range formula and the implications of the angle of projection on the cannonball's trajectory. Questions arise regarding the feasibility of reaching the car given the initial conditions and the relationship between the cannonball's motion and the car's movement.

Discussion Status

Some participants have suggested that the maximum range of the cannonball should be calculated to determine if it can reach the car, especially considering the car's movement. There is an ongoing exploration of how the angle and time variables interact in this scenario.

Contextual Notes

There is uncertainty regarding the values of the angle and time, as well as the assumption that the cannonball can cover the distance to the car based solely on its initial velocity. The discussion highlights the need to consider both the cannonball's range and the car's speed in the analysis.

Not a Wrench
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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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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?
 
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...
 
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.
 

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