# Jumping Bean Physics

1. Aug 27, 2006

### shoook

A jumping bean jumps vertically upward from the edge of a table. It has a speed of 10 m/s when it reaches half of its maximum height.
a. How high does it rise?
b. What is its velocity and acceleration 1 second after it jumps?
c. 3 seconds after?
d. What is its average velocity during the first half second?

Okay so I'm a big noob. I think the acceleration is 9.8 m/sec^2 due to gravity. I think I can add 9.8 m for every second it rises but I'm not sure. Any help at all with this problem is greatly appreciated.

2. Aug 27, 2006

### Staff: Mentor

Not quite. The bean jumps vertically, but gravity is acting downward, so once the bean is launched with some initial velocity, it starts slowing down.

Let H = maximum height, at which point the vertical velocity is zero.

at h = H/2, v = 10 m/s, and the acceleration, g = 9.8 m/s2.

How about writing some equations that relate height h(t), time t and vertical velocity v(t)?

3. Aug 27, 2006

### Saketh

Do you know the kinematic equations?

As in $$\Delta x = v_0 t + \frac{at^2}{2}$$?

If you don't, then I can see why you're having trouble with this problem.

4. Aug 27, 2006

### shoook

No I don't. I've only been taught 5 very basic physics formulas such as
a= Vf - Vi/t