# 2 Balls

1. Jul 30, 2005

### Bama

Identical balls are rolled down 2 inclined planes of the same height but different inclines. Do they reach the bottom at the same time. Neglect friction and air resistance.

Do the balls have the same speed upon reaching the bottom of the incline?

2. Jul 30, 2005

### aliciaw0

do u mean planes of the same length?

3. Jul 30, 2005

### Bama

In my homework assignment, it doesn't mention length. Alicia0

4. Jul 30, 2005

### OlderDan

The inclines cannot have the same length. The balls start from the same height, but one rolls down a shorter plane at a steeper angle.

The first question requires that you think in terms of forces and acclerations. The second is best thought about in terms of energy.

5. Jul 31, 2005

### mukundpa

If the friction is neglected the balls will slide, will not roll at all.

6. Jul 31, 2005

### HallsofIvy

Staff Emeritus
Imagine one incline almost vertical. How long would it take the ball to reach the ground?

Imagine the other incline with a tiny angle from the horizontal so its length is one mile. How long do you think it will take the ball to cover that one mile?