# I need help for school

1. Dec 6, 2003

### UltraPhysical

I am a high school student who needs help understanding some aspects of Physics. My main areas of deficiency are: Average Speed while falling for time,t: Vave= (1/2)v , and projectile motion on the moon.
(1/2)at
I am really struggling to grasp these concepts so please dumb it down for me.

thank you,

UltraPhysical

2. Dec 6, 2003

### Integral

Staff Emeritus
A falling body accelerates at g, so if at time t0 your falling body has veloicity V0 some at later time say t1 it will have a velocity V1. The average velocity will be

$$V_{ave} = \frac {V_1 + V_0} 2$$

This is the same average that you should be used to when averaging any set of numbers. Now if you are considering a body which starts at rest V0=0 so the average velocity is simply V1/2 which appears to be the formula you have. A key thing to know is that this only applies to a body which is starting with 0 velocity.

The only difference between projectile motion on the earth and the moon is the value of the acceleration due to gravity. That of the moon is usually taken as g/6.

I am not sure what the expression you have written is or what it has to do with projectile motion, it represents half the velocity at some some time t. (Perhaps an average?)
That help any?

Last edited: Dec 6, 2003