# How to calculate initial velocity and launch angle? (Projectiles)

• puppy143158
In summary, the conversation discusses the use of a bean bag launcher to shoot a bean bag at a corn hole board. The bag is released from a height of .61m and the board is 5.18m away. The back of the board is .31m off the ground and has a constant slope. The bean bag takes .900 seconds to reach the back of the board when launched at an initial angle. The goal is to find the original velocity and launch angle.
puppy143158

## Homework Statement

A bean bag launcher is used to shoot a bean bag at a corn hole board. The bag is released at a height of .61m above the ground. The front of the board is 5.18m from the location where the launcher releases the bean bag. The back of the board stands .31 m off the ground; the board has a constant slope.

It takes .900 seconds for a bean bag to reach the very back of the board when launched at some initial angle. Given this information, find the original velocity of the bean bag as it is launched, and the angle of launch.

## The Attempt at a Solution

Last edited by a moderator:
Welcome to PF, puppy143158

You have shown know attempt at a solution, which is against the PF rules. You have been warned.

Here is a hint:

- you know the starting and ending heights. Plugging these, along with the flight time, into the equation for vertical distance vs. time should allow you to solve for the vertical component of the velocity.

## 1. How do I calculate initial velocity for a projectile?

To calculate initial velocity for a projectile, you will need to know the distance the object will travel, the time it takes to travel that distance, and the acceleration due to gravity. You can use the formula v = d/t to find the initial velocity. Make sure to use consistent units for distance and time.

## 2. What is the formula for calculating launch angle?

The formula for calculating the launch angle of a projectile is θ = tan⁻¹(vy/vx), where vy is the vertical component of velocity and vx is the horizontal component of velocity. This formula can be derived from the trigonometric relationship between velocity components and launch angle.

## 3. Can I use the same formula for calculating initial velocity and launch angle for all projectiles?

Yes, the same formula can be used for all projectiles as long as the initial conditions (distance, time, and acceleration due to gravity) are known. However, the values for initial velocity and launch angle may vary depending on the specific projectile and its trajectory.

## 4. How does air resistance affect the calculation of initial velocity and launch angle?

Air resistance can affect the calculation of initial velocity and launch angle by reducing the distance and time traveled by the projectile. This can result in a lower initial velocity and a different launch angle than expected. To account for air resistance, more advanced equations and techniques may need to be used.

## 5. Is there a more accurate way to calculate initial velocity and launch angle for projectiles?

Yes, there are more advanced methods for calculating initial velocity and launch angle for projectiles, such as using kinematic equations and accounting for air resistance and other external factors. It is important to use the most appropriate method for the specific projectile and its conditions to ensure accurate results.

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