How Do You Calculate Projectile Motion with Forces in Multiple Directions?

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In summary, the problem involves a projectile being fired with an initial velocity of 300 ft/s down the y-axis and hitting a target 500ft away. There are two constant forces acting on the projectile - one in the negative z direction at 60ft/s and the other in the negative x direction at 45ft/s. The goal is to find the angle of elevation (theta) of the launch, the angle of correction (Beta) in the x direction, the vector valued function r(t) representing the path of the projectile, the total distance traveled by the projectile, the maximum height reached by the projectile, and the time it takes for the projectile to hit the target. The kinematic equations will be needed to solve the problem
  • #1
ch2kb0x
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Homework Statement



A projectile fired down the y-axis with V0 = 300 ft/s, hits a target 500ft away. Assume constant force is acting on projectile at 60ft/s in negative z direction. Assume second constant force acting on projectile in negative x direction at 45ft/s.

Find angle of elevation (theta) of the launch and angle of correction (Beta) in x direction.

Find vector valued function r(t) representing path of projectile.

Find total distance traveled by projectile.

Find maximum height reached by projectile.

Find time it takes projectile to hit target.

Homework Equations


Kinematic equations.

The Attempt at a Solution



The constant force from negative z and negative x directions are completely throwing me off. Help would be appreciated, taking me through step by step. Thank you.
 
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  • #2
ch2kb0x said:

Homework Statement



A projectile fired down the y-axis with V0 = 300 ft/s, hits a target 500ft away. Assume constant force is acting on projectile at 60ft/s in negative z direction. Assume second constant force acting on projectile in negative x direction at 45ft/s.

Find angle of elevation (theta) of the launch and angle of correction (Beta) in x direction.

Find vector valued function r(t) representing path of projectile.

Find total distance traveled by projectile.

Find maximum height reached by projectile.

Find time it takes projectile to hit target.

Homework Equations


Kinematic equations.

The Attempt at a Solution



The constant force from negative z and negative x directions are completely throwing me off. Help would be appreciated, taking me through step by step. Thank you.

You will need to modify your treatment of the Z motion with the additional velocity they provide. (And the X velocity affects X displacement.)

Note they call it a force, though it's not in the units of Force. They apparently want you to treat it as a constant velocity adjustment.
 
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  • #3


As a scientist, it is important to approach problems systematically and use the appropriate equations and principles to solve them. Let's break down the problem and go step by step.

1. Finding the angle of elevation (theta):
We can use the kinematic equation for displacement in the y-direction to solve for the angle of elevation:
y = y0 + v0y*t + (1/2)*ay*t^2
where y0 = 0 (since the projectile is fired from the origin), v0y = V0*sin(theta), and ay = -60 ft/s^2 (since the constant force is acting in the negative z-direction).
Plugging in the values given in the problem, we get:
500 ft = 0 + (300*sin(theta))*t + (1/2)*(-60)*t^2
Simplifying, we get:
500 = 150t - 30t^2
Solving for t using the quadratic formula, we get two possible values: t = 5 s or t = -10/3 s. Since time cannot be negative, we can discard the negative solution and use t = 5 s.
Now, we can use the kinematic equation for the x-direction to solve for the angle of elevation:
x = x0 + v0x*t + (1/2)*ax*t^2
where x0 = 0, v0x = V0*cos(theta), and ax = -45 ft/s^2 (since the constant force is acting in the negative x-direction).
Plugging in the values given in the problem, we get:
500 ft = 0 + (300*cos(theta))*5 + (1/2)*(-45)*5^2
Simplifying, we get:
500 = 1500*cos(theta) - 112.5
Solving for cos(theta), we get:
cos(theta) = 0.375
Taking the inverse cosine, we get:
theta = 67.5 degrees.

2. Finding the angle of correction (Beta) in the x-direction:
Since the projectile is fired down the y-axis, there is no initial velocity in the x-direction. Therefore, the angle of correction (Beta) will be 90 degrees.

3. Finding the vector valued function r(t):
To find the path of the projectile, we can use the parametric equations for motion:
x = x0 + v0x*t + (
 

FAQ: How Do You Calculate Projectile Motion with Forces in Multiple Directions?

What is kinematics/motion in 3-space?

Kinematics/motion in 3-space is a branch of physics that studies the movement of objects in three-dimensional space. It involves analyzing the position, velocity, and acceleration of objects as they move through space.

How is kinematics/motion in 3-space different from kinematics/motion in 2-space?

Kinematics/motion in 3-space is different from kinematics/motion in 2-space in that it takes into account movement in three dimensions instead of just two. This means that objects can move not only left and right, but also up and down and forward and backward.

What is the difference between position, velocity, and acceleration in kinematics/motion in 3-space?

In kinematics/motion in 3-space, position refers to the location of an object in three dimensions at a specific point in time. Velocity is the rate of change of an object's position over time, while acceleration is the rate of change of an object's velocity over time.

How is kinematics/motion in 3-space used in real life?

Kinematics/motion in 3-space is used in various real-life applications, such as in engineering, robotics, and video game development. It is also important in understanding the movement of celestial bodies and the mechanics of flight.

What are the basic equations used in kinematics/motion in 3-space?

The basic equations used in kinematics/motion in 3-space include the equations for position, velocity, and acceleration, which are derived from the fundamental equations of motion:
Position (x) = x0 + v0t + 1/2at2
Velocity (v) = v0 + at
Acceleration (a) = (v - v0)/t
where x0 is the initial position, v0 is the initial velocity, t is time, and a is acceleration.

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