# Few Questions

1. Dec 18, 2003

### EK03

I got some questions that im blanking out on, if someone could tell me what forumla i use i would greatly appriciate it. 1 problem is about a space shuttle taking off that takes 200 seconds to reach its cruising speed of 11,200 m/s or 25 thousand mph, i have to find out at what rate it accelerates.
2. to calculate a G I divide the acceleration by 10 correct?
3. how do i calculate the weight of the rocket? I have the accelration, mass and force information of it i just need a formula
4. how can i calculate the air friction? its got 20% more magnitiude then the weight of the rocket.

2. Dec 18, 2003

### Jupiter

This depends on whether the acceleration is uniform. If it is, then
$$a=\frac{v_f-v_i}{\Delta t}$$

No. At the surface of the Earth g=9.8m/s2. To calculate g, you can divide the weight of an object by its mass.
$$w=mg$$
Or you can plug in the Earth's radius into
$$\frac{F}{m}=g=\frac{GM}{r^2}$$, where M is the mass of the Earth and G=6.67x10-11Nm2/kg2

Again, w=mg.

The weight is w=mg. The friction force is 20% greater than this, so
Ff=(1.2)w

Hope that helps!