Projectiles: Launch speed and horizontal distance

AI Thread Summary
The discussion focuses on calculating the launch velocity and horizontal range of a projectile. The user correctly calculates the launch velocity at 23.0 m/s for a projectile shot straight upwards with a flight time of 4.70 seconds. To find the horizontal range when launched at a 45-degree angle, the user needs to determine the vertical and horizontal components of the launch speed using sine and cosine functions. The vertical component helps confirm the flight time, while the horizontal component, multiplied by the flight time, provides the range. A step-by-step guide on applying these principles is requested for clarity.
gratsoy
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New to the forums, just starting a physics 11 course online and having some troubles with formulas.

Homework Statement



Projectile shot straight upwards, flight time = 4.70 sec
Second Launch at 45 degrees (horizontal range approx. 50-60 meters

A) Find Launch Velocity
B) Find Horizontal Range when shot at 45 degrees

Homework Equations



d = vit +1/2gt2

V = - 1/2gt ("made" this one myself from above formula, unsure if correct)


The Attempt at a Solution




Launch velocity

V = - 1/2gt
g = -9.8m/s
t = 4.7s

V = -[((1/2(-9.8))(4.7)]
V = -((-4.9)(4.7))
V = 23.0 m/s


I have no idea how to calculate the horizontal range, I need a formula that incorperates the 45 degrees

Thanks in advance!
 
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gratsoy said:
New to the forums, just starting a physics 11 course online and having some troubles with formulas.

Homework Statement



Projectile shot straight upwards, flight time = 4.70 sec
Second Launch at 45 degrees (horizontal range approx. 50-60 meters

A) Find Launch Velocity
B) Find Horizontal Range when shot at 45 degrees

Homework Equations



d = vit +1/2gt2

V = - 1/2gt ("made" this one myself from above formula, unsure if correct)

The Attempt at a Solution




Launch velocity

V = - 1/2gt
g = -9.8m/s
t = 4.7s

V = -[((1/2(-9.8))(4.7)]
V = -((-4.9)(4.7))
V = 23.0 m/sI have no idea how to calculate the horizontal range, I need a formula that incorperates the 45 degrees

Thanks in advance!

Homework Statement


Homework Equations


The Attempt at a Solution


You can work from first principles: Calculate the vertical and horizontal components of the launch speed - using sin45 and cos 45 factors.
The vertical component let's you calculate the flight time, the horizontal component with that time let's you calculate how far away it will land - the range.
Many Physics texts will have a section where a formula is derived, so you can simply substitute the 23 m/s to get an answer [assuming 23 m/s is correct - it certainly is a reasonable answer]
 
PeterO said:
You can work from first principles: Calculate the vertical and horizontal components of the launch speed - using sin45 and cos 45 factors.
The vertical component let's you calculate the flight time, the horizontal component with that time let's you calculate how far away it will land - the range.

How would I do this? I am completely new to this and need a formula with a simple step-by-step guide on how to implement that formula to derive the answer.
 

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