A concrete highway is built of slabs 12 m long .How wide should be the expansion cracks between the slabs at 15 Celsius to prevent buckling if the range of temperature is -30 to 50 Celsius?

Explanation:

Given:

Change in length due to temperature can be  given as:

Now at temperature 15°C:

Hence the expansion crack between the slabs at this temperature must be:

prolly a beacuse the momentuem the car has increases while going down hill

current flows in a wire