# Need help with some basic questions

1. Dec 6, 2006

### pack60

can someone help me with some basic questions

2. Dec 6, 2006

### NTUENG

Mind typing your question so that we can help??

3. Dec 7, 2006

### pack60

questions I need help with

When final velocity is larger than initial velocity, then acceleration is what?

What affects the time that a horizontally projected object remains in the air?

What components of projectile are affected by gravity?

4. Dec 7, 2006

### Staff: Mentor

What are your thoughts on these questions? What equations are relevant? We can only help you if you show some of your own work on the problems.

5. Dec 7, 2006

### pack60

1st question: I am thinking that acceleration is positive

2nd question: initial vertical velocity and relative projection height

3rd question: the vertical components, but not sure if their are specific vertical components

6. Dec 7, 2006

### Staff: Mentor

You got them right.

7. Dec 7, 2006

### pack60

thanks im new to this stuff and I am trying to figure it out. got time to help on more?

8. Dec 7, 2006

### pack60

when it says the components of vector mechanics, are they just talking about the x and y components? Or the horizontal and vertical compponents?

9. Dec 7, 2006

### Staff: Mentor

The components are just the breakdown of the vector in whatever coordinate system you are using at the time. That could be left/right, forward/backward, up/down. Or (x,y,z). Or lots of other possibilities. (x,y,z) is just a little easier to work with compared to left/right, forward/backward, up/down.

10. Dec 7, 2006

### pack60

thanks. next one
A ball is kicked with an initial velocity of 10 m/s at an angle of 30 degrees. Neglecting air resistance, what is the speed of the ball at landing?

Answer: 10 m/s, the ball will slow down on the way up and speed back up on the way down, maxing out at the initial velocity