# Simple True/False Question

1. Jan 24, 2005

### sundrops

The maximum height reached by a projectile depends on the horizontal velocity component.

True or False

Here's my reasoning - the maximum height is reached when y=0, so in that case the maximum height depends on the horizontal velocity component. I'd like to hear your guys thoughts on this. I only get 1 shot at getting this right so I wanna hear what you guys think!

2. Jan 24, 2005

### dextercioby

FALSE.Can u see why?

Daniel.

3. Jan 24, 2005

### sundrops

is it because of gravity?

4. Jan 24, 2005

### dextercioby

Since it's the only force acting on the projectile (neglecting Magnus effect,aerodynamic force,Stokes force,Coriolis force) i'd say yes...

Daniel.

5. Jan 24, 2005

### cepheid

Staff Emeritus
Yeah....the KEY point of projectile motion as modelled in school is that horizontal and vertical components of the projectile's velocity are independent. That's what they want you to remember.

6. Jan 24, 2005

### sundrops

alright thx guys

7. Jan 25, 2005

### Tide

You left out the finite size of the planet which brings the inverse square law into play! :-)

8. Jan 25, 2005

### dextercioby

He asked me about gravity,not the inverse square law and where it comes from...And besides,everything reduces to solving Einstein's equations,right...??

Daniel.

9. Jan 25, 2005

### marlon

and to continue dexter's nitpicking, he also forgot to incorporate the fact that the earth is not a perfect sphere...Where are them Legendre-terms in the potential ???

marlon

10. Jan 25, 2005

### dextercioby

"The maximum height reached by a projectile depends on the horizontal velocity component."

Do you see any Earth nonspherical,here???

Daniel.

11. Jan 25, 2005

### marlon

do you see any coriolis,blablabla here ???

gravity also changes when you take into account a non-spherical earth

marlon

12. Jan 25, 2005

### dextercioby

The PLANET/celestial body (with atmosphere) A PRIORI SPHERICAL IS ASSUMED ROTATING...

I AGREE with the second part...

Daniel.