CHECK OUT WHY DO SOME FORMULA 1 TYRES HAVE NO TREAD ON THEM !!

When you take the car for an MOT, one of the things they have to check for is the depth of tread left on your tyres. Anything below 1.6 millimetres is not allowed and can affect your breaking distance.

So why are some Formula 1 car tyres completely smooth?

The job of a tyre is to grip on to the road surface. Because the tyre is made of a very ‘grippy’ material there is a lot of friction between the tyre and the road. Friction is a very useful force that can slow you down and stop you slipping all over the place. Some Formula 1 cars use completely smooth tyres in dry weather. A completely smooth tyre has lots of contact between the rubber and the road so these smooth tyres give great grip for fast corners.

When you’re driving around in your hatchback in city, you can’t pull in at a pit-stop to have your tyres changed when the clouds open, so normal cars need tyres that can grip in all weathers. The tread patterns on the rubber do not help with grip, but are there to channel water off the road. If you let your tread get too shallow, the water can’t go anywhere and the wheels can skim along over the surface of the water. This is called ‘aquaplaning’ and is nasty for a car on any road, but could be much worse for a Formula 1 driver because of the speeds that they drive. So they can choose from a whole range of tyres to use during a race depending on the weather. Dry weather races are usually faster and more exciting because of the extra grip the smooth tyres can give on the race track.

WHY WIND TURBINES HAVE 3 BLADES? WHY NOT 2 OR 4??

Like many design considerations, the number of blades on a wind turbine is a compromise. Each blade disturbs the air for the following blade, so ideally you want as few blades as possible to maximize efficiency.

If you've ever had the chance to watch a wind turbine start, you would have noticed that the blades start rotating very slowly and then begin accelerating faster and faster. This is because of the aerodynamic design of the blades.

The more blades there are on a wind turbine, the higher will be the torque (the force that creates rotation) and the slower the rotational speed (because of the increased drag caused by wind flow resistance). But turbines used for generating electricity need to operate at high speeds, and actually don't need much torque. So, the fewer the number of blades, the better suited the system is for producing power.

ONE BLADED TURBINE :

Theoretically, a one-bladed turbine is the most aerodynamically efficient configuration. However, it is not very practical because of stability problems. 

TWO BLADED TURBINE :

Turbines with two blades offer the next best design, but are affected by a wobbling phenomenon similar to gyroscopic precession.(gyroscopic precession is the phenomenon in which the axis of a spinning object describes a cone in space when an external torque is applied to it.)

Also in case of 2 bladed turbine,since a wind turbine must always face into the wind, the blades will have to change their direction vertically when there is a shift in wind direction.2 bladed turbine will become completely vertical and completely horizontal once in a rotation.This will result in vibrations.

THREE BLADED TURBINE :

On the other hand, a turbine with three blades has very little vibration or chatter. This is because when one blade is in the horizontal position, its resistance to the yaw force is counter-balanced by the two other blades. So, a three-bladed turbine represents the best combination of high rotational speed and minimum stress.

The more blades you add to the system, the more the cost of producing it. This may seem obvious, but every pound counts when you are trying to produce energy from a turbine, and going to a 4 turbine system is going to cost more to produce.

TRUE STRESS VS ENGINEERING STRESS EXPLAINED !!!

Stress is defined as the resistance force acing per unit cross section area of the body. It is also defined as the ratio of applied load to the cross section area of the body.It is an internal property of the material.True stress and Engineering stresses are a bit different. 

Let us take the example of tensile test.Before doing the tension test we have to determine the length and diameter of the specimen and we assume these parameters remain constant throughout the whole experiment. So when we calculate the stress by the formula-

 Stress= Force/Area

we actually calculate the stresses (corresponding to different strains) for the given value of diameter which we have calculated in the beginning of experiment. These stresses are called Engineering Stresses.but as we do the experiment we observe a phenomenon called necking and till now we have been neglecting any such necking which takes place. So let's see what happens when there is necking.

So, As we can see as the bar is subjected to tensile forces just like what happens in a tension test experiment and after certain instant a neck like region forms. This shows the cross-section of the specimen has changed as the experiment proceeds further.

Hence whatever we  will get the stresses now will be different from the ones we got when we we assumed the cross-section remained constant. These stresses are called TRUE STRESSES. True stresses are thus force divided by the area of the section at that instant.

(It should be noted that only after the necking starts there is a considerable change in the cross-section and thus the variation between the two stresses becomes more prominent).

INDUSTRIAL HELMET COLOUR CODE EXPLAINED !!!

You might have seen various employees of a factory wearing a hard hat of different color!!Let's understand the meaning of this color code!

Hard hats are made from hardened plastic and, as such, they have an expiry date because plastic deteriorates over time.  This means that they will need to be replaced periodically so it’s important that you check the expiry date on any hard hat that you use.  A hard hat’s service life starts when it is first used and that date should be recorded on the hat in indelible pen.  The maximum time for replacing a hard hat is five years, but it should be checked regularly for signs of wear or damage.  The hard hat suspension should be replaced on an annual basis – they’re widely available from work gear outlets.

Hard hats come in a range of colours, all of which are significant as it allows workers on site to identify who is who and what type of work they are undertaking.

KNOW THE MEANING OF A/F ON NUMBER PLATE IN NEW VEHICLES !!!!

A/F stands for Applied For. This was a previous notation on the newly bought number plates of the vehicles. Every vehicle needs to be registered under the Motor Vehicle Act 1989.

Yes,it's illegal to drive with an A/F plate in India and can attract heavy fine and even car can be bonded. Every car that rolls off the showroom now gets either a temporary number or a permanent number according to the state.

The Central Motor Vehicles Rules (CMVR) do not allow driving a vehicle without registration. To drive a vehicle even with the `A/F' (Applied For) status is an offence. "It is a misconception that people can drive with an A/F tag,"

CHECK OUT WHY NEW TYRES HAVE RUBBER HAIR ON THEM !!

There are little rubber hairs that you see on every new tire. Technically, they are called vent spews, which gives away their purpose for being on the tire. Many people think these hairs play a role in noise reduction or indicate wear but their primary purpose is air ventilation.

Those little rubber hairs are a byproduct of tire manufacturing. In a tire mold, rubber is injected and air pressure is used to force the liquid rubber into all the nooks and crannies. In order for the rubber to completely fill the mold, small pockets of air need to be able to escape.

There are small vent holes in the mold so trapped air can find a way out. When the air pressure forces the liquid rubber into all the orifices, a tiny bit of rubber makes its way out of the vent holes as well. These rubber bits firm up and remain attached to the tire when it's removed from the tire mold.

Though they serve no purpose in your tire’s performance, the tire hairs' presence is an indication that a tire is new. Tires that have been in service for some time, coupled with environmental effects, will eventually wear off the hairs.

CHECK OUT WHY HATCHBACKS HAVE REAR WINDOW WIPER BUT SEDANS DON'T !!!

Rear wipers are essentially meant for vehicles with an upright rear window that collects dust, dirt, snow, etc., because of aerodynamics – the flow of air over the right angle where the roof and rear window meet creates a low pressure area that pulls that nasty stuff in and deposits it onto the surface. 

Sedans, with their sloped roofline rely on that same flow of air – this time over the roof and down the window to keep it clean. Adding a wiper would create more aerodynamic drag creating slightly more fuel use. A wiper also requires an electric motor and a fairly convoluted mechanism and lengthy arm to make the wiper sweep across the glass from side to side. 

SUVs/hatchbacks with window right at the rear has nearly vertical windows, but not the trunk to guide the airflow. It has a low-pressure zone right in that area when it's moving at speed, which will "suck in" water and dirt and thus make the window very dirty.

This is totally based on the concept of aerodynamics !!