Projectile Range: Initial Speed, Gravity, Mass, Angle & Volume

[shinystar716]

I know this is probably a super easy question but I have no idea what the answer is.

Which of the following factors are relevant in determining the range of a projectile that is launched on a very large flat plain (i.e. no hills or cliffs):

- initial launch speed
- acceleration due to gravity
- mass of projectile
- initial launch angle
- volume of projectile

Thanks!

 

[Dick]

Mmm. Any guesses? You have to show you've given the problem some thought in a concrete way.

 

[shinystar716]

I'm pretty sure that initial launch speed and initial angle are factors. My guess would be that acceleration due to gravity wouldn't be since gravity is always the same. I think that the mass must play a roll - the more matter the harder it is to be thrown. And finally I was unsure what they meant by volume of projectile. If that it is talking about how high the projectile goes I don't think that would necessarily be a factor but I"m not sure.

 

[Dick]

Good! Volume of the object is just how big it is, is it a cubic foot or a cubic yard. There is a problem with this question in that it isn't stated very completely. Eg. I think the questioner might expect you to say mass doesn't matter, but your point about larger masses being harder to accelerate is quite correct (like if the launcher were a slingshot with a heavy projectile). Similarly changing volume with a fixed mass doesn't matter if there is no air - if there is, it does. So this is not a "super easy problem", in fact, it's just plain ambiguous. Is that the complete statement? Where did you find it?

 

[Dick]

How about if we change the question a little. Tell me about each factor listed and tell me if it is "always a factor all else held constant" or "could be a factor depending on other assumptions". That might make life a little easier. I agree with you on speed and angle. Don't agree with you on acceleration due to gravity.