# Homework Help: Earth vs Moon

1. Feb 2, 2014

### jdawg

1. The problem statement, all variables and given/known data

Would the horizontal distance traveled by a projectile on earth be the same as one on the moon? I feel like the distances would be different, but when I was calculating the initial velocity of the projectile on the moon I used the same x value(distance) that I did for earth. Wouldn't gravity have an affect on the distance traveled?

2. Relevant equations

Vxoearth=x√(g/2y)
Vxomoon=x√((1/6)g/2y)

3. The attempt at a solution

2. Feb 2, 2014

### Nugso

It would. Gravity affects the maximum height that an object can go, hence it affects time as well, and time affects the horizontal displacement. Can you please show your calculations?

3. Feb 2, 2014

### jdawg

Height: y=14.1cm=0.141 m
Distance: x=31.3 cm= 0.313 m

Vxoearth=(0.313)*√(9.8/2*0.141)=0.19 m/s

Vxomoon=(0.313)*√(1/6*9.8/2*0.141)= 0.745 m/s

But what's confusing me is the way they worded the question. They told me to use my x measurement and y height from the experiment when calculating the initial velocity for the moon. Then they ask if the x values measured on the moon would be the same as the x values measured on earth. Why would they tell me to use the same x value if they would be different?

4. Feb 2, 2014

### SteamKing

Staff Emeritus
As always, please follow the HW template when posting to these forums. We can't judge the wording of the problem if you don't provide it verbatim.

5. Feb 2, 2014

### jdawg

Sorry, I'm still kind of new to this forum. But I think I figured out what the question meant. Thanks for the help!