Sainsbury's nicking petrol off customers?

Money_Grabber13579

But surely you want to stop? I thought the idea of going into a petrol station was to stop and get fuel, no? So why would you want to speed up again after going over the ramp and proceed to drive over the fuel pump?

Lemonade_Pockets

prowla wrote: »

The kinetic energy in a car is produced as a result of the car moving. The car moves because of the engine, which uses petrol.
You cannot seriously think that the motion of a car comes from nowhere?!?!?

Dude - it's braking (not breaking).

If your car presses down on the pad, then either (a) the pad is raised above the road surface so the car has to climb on to it, or (b) it sinks into the road under the weight of the car so that the car has to climb out of the hole. It may be only a centimeter movement either way, but the energy comes from the car, and thus from the fuel burned.
The only way it could be free was if you were freewheeling to the point of energy capture and you did not need to accelerate again after it.

I'm not disputing whether the car will use any extra energy up going over one of these things. Although it would be negligible to anynormal human being, unless you put chocks in your springs and pump your tyres up to 50psi, tape over all the panel gaps on your car to save money as well! What i'm saying is that the energy used by the car is not powering this pad, the two energy equations are not related.

hundredk

prowla wrote: »

The only way it could be free was if you were freewheeling to the point of energy capture and you did not need to accelerate again after it.

This is not free because you would only be freewheeling as a result of the car having momentum and that momentum is from using fuel to gain speed in the first place.

hundredk

Lemonade_Pockets wrote: »

What i'm saying is that the energy used by the car is not powering this pad, the two energy equations are not related.

Energy cannot be lost or made, only transferred. Since the car going over the pad is creating electricity, the energy has to be transferred from the car.

Money_Grabber13579

Yes but you can either transfer it to the pad, or to the brakes, thus wearing them out more quickly. (If we're going to be discussing the loss of a namby bit of petrol, then you MUST consider that if these pads didn't exist, your brake pads would need to be replaced a fraction of a minute earlier.:rolleyes:)

mikey72

Look at number 2, Longleat on
http://www.hughesresearch.co.uk/index.php?option=com_content&view=category&layout=blog&id=29&Itemid=48

The car is powering the pad, by setting a wave motion.
It's not green, it's a car powered wave machine, that could be used as a speed bump, in some places.
Not the entrance to Sainsburys though, that is just hype. One in each parking space perhaps. But then they would be nicking my energy when I back out again.

hundredk

Money_Grabber13579 wrote: »

Yes but you can either transfer it to the pad, or to the brakes, thus wearing them out more quickly. (If we're going to be discussing the loss of a namby bit of petrol, then you MUST consider that if these pads didn't exist, your brake pads would need to be replaced a fraction of a minute earlier.:rolleyes:)

Yes but the OP's question was "isn't this effectively nicking petrol out of your tank to power their store? " The answer to that is yes. As to what degree I'm sure you're right and it's negligable, as would be the savings on brakes.:D

And if you walk over it they're nicking the food out of your mouth:rotfl:

Money_Grabber13579

hundredk wrote: »

Yes but the OP's question was "isn't this effectively nicking petrol out of your tank to power their store? " The answer to that is yes. As to what degree I'm sure you're right and it's negligable, as would be the savings on brakes.:D

And if you walk over it they're nicking the food out of your mouth:rotfl:

Well maybe they'll be able to cut prices then!:D

trevormax

The idea is you were going to stop at that point anyway. You will not be accelerating again after you go over the plate because the whole, entire point of you being there at that point in space is to STOP at the pumps to get fuel. Unless you are incredible at being able to judge where you will stop when you start to freewheel, and you dont care that it takes you half an hour to get from the entrance of the petrol station to the pump.

This is green energy in a sense as you are recycling energy that would otherwise have been wasted by using brakes, plus using a small amount of energy from gravity (note, not creating energy but transferring it from potential to kinetic energy).

However, the amount of energy that is transferred by using the plate is insignificant, maybe even less than a penny each time a person rolls over one of these plates. However there are so many people going over the plate that it all adds up.

By using the plate, they are not stealing anything from you. They are using energy that you are wasting. Simple.

LandyAndy

mikey72 wrote: »

Look at number 2, Longleat on
http://www.hughesresearch.co.uk/index.php?option=com_content&view=category&layout=blog&id=29&Itemid=48

The car is powering the pad, by setting a wave motion.
It's not green, it's a car powered wave machine, that could be used as a speed bump, in some places.
Not the entrance to Sainsburys though, that is just hype. One in each parking space perhaps. But then they would be nicking my energy when I back out again.

Surely by reversing you'd be sucking the energy back out of the store and into your car?;):D