In a hypothetical situaltion...?

Question

If a person was in a vehicle that would accelerate faster at a slow rate, and slow down, but still maintain some of the additional velocity from the fast acceleration, and alternated this process
for awile, could the vehicle eventually reach a very fast velocity, and the passenger would not experience a large gravity factor (not many g's)?

Answer 1

The force a person feels while accelerating (the “g” force) is not a function of the person’s velocity but of their acceleration.

1 “g” refers to the accelerating due to gravity which accelerates all objects on the surface of Earth downward at a constant rate of 9.81 m/s^2.
The term can also be used when describing the accelerating of bodies in terms of multiples of the gravitational acceleration for comparison purposes. For example, if something was experiencing 5 “g”s, they would be accelerating at 5 times the normal rate that gravity would cause.
In any case, the “g” force is not depending on the speed the object is traveling, just its acceleration.

Force = mass * acceleration

If you wanted to increase your velocity up to some very high value without experiencing too many “g”s, then what you would need to do is to accelerate at a low rate for a longer time in order to cause the same change in velocity.

Change in velocity = acceleration * time

Let’s say you are at rest, not moving, and you want to increase your velocity to 1000 m/s (2236 miles per hour). The time it will take for you to achieve this final speed depends on the rate of acceleration.

If you were to accelerate at, for example, 100 m/s^2, it would only take you 10 seconds to reach this fantastic speed…but in the process you would be experiencing almost 10 “g”s of acceleration.
1000 m/s = 10 m/s^2 * 10 second

10 “g”s is a very high acceleration and a lot of people could not take this strain on their bodies. So instead lets say you decided to only accelerate at 1 m/s^2. In this case you would eventually reach your goal of 1000 m/s in 1000 seconds (about 16.7 minutes). In the process, the person accelerating would only experience about 1/10 of a “g”.
1000 m/s = 1 m/s^2 * 1000 second

The trade off between these two situations is the time it takes to achieve the final desired velocity. It takes longer if you accelerate at a lower rate, but in the end you will get to the very same speed.

You will not need to start/stop accelerating or accelerate and then slow down to reduce the “g” force effects, you can maintain a constant (but low) accelerating and still eventually reach high speeds.

Answer 2

There are two ways for a space-ship to reach a desired velocity. The first way is to accelerate constantly till you reach the desired speed. This would be like a rocket turning on it's engines and then cutting them off when the desired velocity is reached. In space, inertia will keep the ship moving at the same velocity.
The second way is to give the ship little "pushes" till it reaches the desired speed. This would be like an ion-engine that only shoots out one high-speed ion every minute(for example). When each ion is shot out the back, the ship will accelerate just a little bit and then settle into a new constant velocity. After enough ions are shot out the desired velocity will be reached.
To answer your question, there is no known way to reach a very high speed really fast without the passengers experiencing the corressponding accelleration and G's. The best we can do slow down the acceleration and spread the G's over a longer time. In the first example, the rider would be pushed into the back of his chair for as long as the thrusters were firing. In the second example(if each ion is moving fast enough), the rider would only feel G's at the moment the ion is ejected.
There is one way that a ship could accelerate at 10 G's with the rider only feeling 1 G.......
Imagine a really long space-ship with a railroad track going from the front to the back inside. Now put the rider in a chair at the front of the ship and have the chair mounted on the track. Make it so that the chair can slide back on the track, but experiences drag when it moves.
If the ship travels 98 meter in one second from a dead stop, the rider would normally feel 10 G's. But if the rider in the moving chair were to slide back wards at a speed of 49 m/s at the moment of the ship's forward acceleration, he would only feel 5 G's If he were to slide back at a speed of 960.4 m/s he would only feel 1 G.
Then, when you are done accelerating, you can move the chair back to the front.

Answer 3

It sounds like the passenger is going to experience a jerky ride. The way to make your passenger most comfortable during an acceleration is to accelerate slowly up to constant acceleration, accelerate for the needed time, then ease off slowly to no acceleration once you get up to the desired speed. If you want less g's, you just need to spread the acceleration out over a larger time.

Answer 4

Of course. Happens all the time. Ever go 80 miles/hr without noticing and then have a cop pull you over???