# Help with physics projectile motion question?

Hello. I'm doing a physics lab and one of the Analysis/Evaluation questions is "Explain why the vertical component of a projectile motion on an inclined plane is independent of the horizontal component"

The lab involves having a sparker with air coming out of the bottom (like an air hockey table) slide on an inclined plane in 3 different types of projectile motion. One of them is just going up and back down, the other is when it's pushed horizontally and falls down due to the inclined plane, and the last type of motion is when both the x and y component have a initial velocity. I know the answer i just don't know how to explain it properly. Any help would be appreciated. Thanks!

Relevance

the fundamental reason is that the forces acting in the horizontal and vertical directions are at right angles to each other

in the absence of friction the vertical is influenced by gravity alone

• Login to reply the answers
• A bit awkward to explain. But here's my version.

Some Background

In the equation 'F=ma', F is usually taken to be the resultant force and a as the resultant acceleration.

But the equation (F=ma) is also true in ANY given direction providing F is the component of the resultant force in that direction, and a is the component of the resultant acceleration in that direction.

____________________________

In the experiment, there is no horizontal force (assuming friction is negigible). So in a horizontal direction, there is no acceleration and the horizontal component of velocity remains constant.

In the vertical direction the total force equals the component of weight parallel to the incline. This is constant, so the vertical component of acceleration is constant (and downwards) causing a uniform increase in the vertical component of velocity with time.

• Login to reply the answers
• Explain Projectile Motion

• Login to reply the answers