Projectile: Find initial velocity without time

In summary, to determine the initial speed of snow at angle 40 degrees, you can use the equations L = v0 t cosθ and Δy = v0 t sinθ - (1/2) g t2 and solve for v0 by substituting the first equation into the second and solving for v0. This method was confirmed to be correct by the professor.
  • #1
JJBladester
Gold Member
286
2

Homework Statement


Knowing that snow is discharged at an angle of 40 degrees, determine the initial speed, v0 of the snow at A. Answer: 6.98 m/s

Homework Equations



snow%20thrower.jpg


projectile.jpg


The Attempt at a Solution



I have found the x and y velocity and position formulas. Now since I don't know time, should I solve both position equations for time (t) and set them equal to each other to get my only unknown, vi? The quadratic equation for time in the y-dir seems a bit hectic. Is there an easier way to go about trying to find vi?
 
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  • #2
Start with
L = v0 t cosθ
Δy = v0 t sinθ - (1/2) g t2

Solve the first equation for t and replace in second equation. Solve the ensuing equation for v0.
 
  • #3
kuruman said:
Start with
L = v0 t cosθ
Δy = v0 t sinθ - (1/2) g t2

Solve the first equation for t and replace in second equation. Solve the ensuing equation for v0.

I believe this is what you had in mind. The answer matches the professor's answer. Thanks again kuruman!

projectile%20final.jpg
 

1. What is a projectile?

A projectile is any object that is thrown or launched into the air and moves along a curved path due to the force of gravity acting upon it.

2. How is initial velocity defined?

Initial velocity, also known as initial speed, is the velocity of a projectile at the moment it is launched or thrown.

3. Why is it important to calculate initial velocity?

Calculating initial velocity is important because it helps us understand the motion of a projectile and can be used to determine its trajectory and landing point.

4. What information is needed to find initial velocity without time?

To find initial velocity without time, we need to know the initial height of the projectile, its final height, and the distance it travels horizontally.

5. What is the formula for finding initial velocity without time?

The formula for finding initial velocity without time is: V0 = √(2gh + dx), where V0 is the initial velocity, g is the acceleration due to gravity (9.8 m/s2), h is the initial height, and dx is the horizontal distance traveled.

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