why do you lurch forward and backward when the bus slows down and picks up speed according to newtons law?

Answer 1

Good question. A fundamentally good question indeed.


Newton has answered that with his First Law: "Every body perseveres in its state of being at rest or of moving uniformly straight ahead, except insofar as it is compelled to change its state by forces impressed. [Cohen & Whitman 1999 translation]" http://en.wikipedia.org/wiki/Inertia

Was it not a bit stuffy? Well, then one can say that it is due to the concept of inertia and “inertia is the tendency of a body to maintain its state of rest or uniform motion unless acted upon by an external force.” http://en.wikipedia.org/wiki/Inertia_%28disambiguation%29

If all that did not gave you a warm and comfortable feeling of enlightenment then just realize that any material object, that has any mass, is always stubbornly resists being moved and this stubbornness which is incidentally proportional to its mass is inertia. It is the heart of Newton’s First Law (and Second and Third).

So when the bus slows down your body wants to continue to maintain the same speed as before. Relatively speaking, at least from your perspective, the bus is moving backwards as you continue to maintain earlier speed. This is why you lurch forward when the bus is slowing down and lurch backward when it accelerates.

This is why Newton insisted in his first law that if object will move with constant speed or remain at rest if the net force applied to them is zero. If that net force is not zero then the object will slow down or accelerate, however that takes us into his Second Law.

I hope it was fun

Answer 2

Newton's law - A body in motion tends to remain in motion unless acted upon by another force.

While you are riding in a bus say at 60mph and the bus slows quickly to 50 mph - your body is traveling at 60mph along with the bus so when it begins to slow you lurch forward until the seatbelt stops you .

Same idea for when speeding up.

Hope this helped!

Answer 3

It has to do with frequency change. Change in frequency within mass is what causes mass to move. As a person accelerates there is a continual increase of frequency within their body until there is no longer a force acting upon them. That frequency change remains until there is some manner by which it may be given to another mass. In your bus, that mass is the braking system as the frequency of kinetic energy is transfered through the brake shoes to the drums and rotors - which frequency heats them up. This same condition is also seen when a nose cone of a rocket reenters earth's atmosphere. The frequency of kinetic energy (hf = mk) is then directly transferred from the forward direction of the nose cone to the molecules of the atmosphere.

An interesting thought is that it is possible to make a "flying carpet" a real one. The condition that must be executed is the same as found in your car or spaceship. Were you to go to http://timebones.blogspot.com the first item that shall come up is the parameters on how this could be done. Not make a flying carpet, that would be too involved, but in how to transform heat energy directly into motion. It's the opposite of what happens in a breaking system.

Answer 4

Newton's 1st law.

When you are stationary, you tend to want to remain stationary but when the bus pull forward, you will lurch backward.

However, once in motion, you would tend to remain in motion. So when the bus slows down, you will lurch forward instead.

Answer 5

Look at the bench you're sitting on. It's attached to the bus, and you're not. Look at what the seat does when the bus speeds up and slows down. Think about Newton's 1st and 3rd laws.

No, I'm not going to do your homework for you!

Answer 6

To add to what's been said: an object in motion tends to stay in motion (the bus stops, but you keep moving forward) unless acted upon by another force (like gravity); an object at rest tends to stay at rest (the bus starts moving, but you want to stay where you are, pushing you back into the seat) unless acted upon by another force (the bus take you away).

Answer 7

Bodies in motion tend to stay in motion unless acted upon by another force.

If you are in a bus going 65 miles per hour, you are also moving at 65 miles per hour (relative to the ground). As the bus slows, you are still moving at 65 miles per hour so you must strain against your leg to slow yourself down as well.

Answer 8

A body in motion tends to remain in motion unless acted upon by another force.

Answer 9

because you are going forward with the bus, and when the bus stops it must stop you also. you are going forward until the bus stops you, thats why you lean forward.
and when the bus goes again, it pulls you abck because you are still and the bus is moving, so it must move you.

Answer 10

It would be because a person needs enough physical strength to alleviate the effects of changing momentum.