# Minimum initial velocity of the projectile launched at what angle

• vneff
In summary, the problem is to find the minimum initial velocity and angle needed for a projectile to clear a 55m high wall located 100m downrange. This can be solved by using two equations, one involving energy and the other involving projectile kinematics, to determine the two unknowns.

## Homework Statement

Assume there is a wall located 100m downrange (x=100) from the projectile launching position (x=0) that is 55m (y=55) high. What is the minimum initial velocity of the projectile launched at what angle necessary to clear the wall?

h=(v^2sin^2α)/2g

## The Attempt at a Solution

I can find the displacement but I'm confused as to how I am supposed to find both velocity and the projectile angle from this information.

vneff said:

## Homework Statement

Assume there is a wall located 100m downrange (x=100) from the projectile launching position (x=0) that is 55m (y=55) high. What is the minimum initial velocity of the projectile launched at what angle necessary to clear the wall?

h=(v^2sin^2α)/2g

## The Attempt at a Solution

I can find the displacement but I'm confused as to how I am supposed to find both velocity and the projectile angle from this information.

2 unknowns, angle and velocity.
Then you have find 2 equations to solve the problem.

vneff said:

## Homework Statement

Assume there is a wall located 100m downrange (x=100) from the projectile launching position (x=0) that is 55m (y=55) high. What is the minimum initial velocity of the projectile launched at what angle necessary to clear the wall?

h=(v^2sin^2α)/2g

## The Attempt at a Solution

I can find the displacement but I'm confused as to how I am supposed to find both velocity and the projectile angle from this information.
Do exactly what azizlwl said. You have two unknowns, so you need two equations to get a solution. You could find one of those equations by considering energy and the other by using projectile kinematics.