# Constant Projections: Parabolic Trajectory - Accel.

• courtney1121
In summary, the only constant factor in a projectile's motion along its parabolic trajectory is its acceleration. While the speed may remain constant as long as the acceleration doesn't change, the velocity and y-velocity will vary due to the changing direction of the projectile. This is true for both 2D and 3D motion.
courtney1121
As a projectile moves along its parabolic trajectory, which of the following remain constant (ignoring air resistance, and defining the z-axis to point upward)? More than one answer may be correct!

a. Its speed.
b. Its velocity.
c. Its x-velocity and its y-velocity.
d. Its acceleration

I am thinking the only thing constant is acceleration. My book keeps saying that the horizontal velocity is constant but this is a parabolic trajectory so shouldn't that make a difference? Also velocity is going to change from positive to negative, and speed will change at different points of the trajectory.

Along the Y axis the acceleration is always constant. The speed is constant as long as the acceleration doesn't change. The velocity would be constant as well as its x velocity, however the Y velocity wouldn't be constant because at the highest peak of the projectile the y velocity would be 0.

well i don't think velocity would be constant cause velocity is magnitude and direction and the direction changes so it would change, I think. I'm pretty sure I'm considering the projectile in the zx plane so y will always be 0.

Oh crap this is 3 dimensional. Scratch my post. I was talking about 2 D.

## What is a constant projection?

A constant projection is a type of motion where an object is projected at a consistent velocity in a straight line. This means that the object's speed and direction do not change throughout the motion.

## What is a parabolic trajectory?

A parabolic trajectory is a curved path that an object follows when it is projected at an angle to the ground. The shape of the trajectory is similar to a parabola, hence the name. This type of trajectory is commonly seen in objects that are thrown, such as a ball or a stone.

## What is acceleration in relation to constant projections and parabolic trajectories?

Acceleration in this context refers to the rate at which the velocity of an object changes. In a constant projection with a parabolic trajectory, the object experiences a constant acceleration due to the force of gravity pulling it towards the ground.

## How is the acceleration of an object calculated in a constant projection with a parabolic trajectory?

The acceleration of an object in this type of motion can be calculated using the formula a = g*sin(theta), where a is the acceleration, g is the acceleration due to gravity (9.8 m/s^2), and theta is the angle of projection. This formula assumes that there is no air resistance acting on the object.

## What are some real-life applications of constant projections with parabolic trajectories?

One common real-life application is in sports, such as throwing a ball or a javelin. It is also used in physics experiments to study the effects of gravity and other forces on objects in motion. Additionally, it is used in the design and testing of projectiles, such as missiles and rockets.

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