Questions

Collisions occur at curves because speed on the approach is too great.

Fluoride deficiency is a disorder which may cause increased dental caries due to a lack of fluoride in the diet. Dental caries or tooth decay is the breakdown of dental tissues by the acidic products released by the "bacterial fermentation of dietary carbohydrates”

If an object moves with some velocity that means the magnitude and direction of the object changes i.e, the object moves with some acceleration. Hence, if the object moves with constant velocity, no change in direction and magnitude of speed i.e, no acceleration = 0 acceleration.

Glass is made from heating of sand. To melt sand to make glass, the temperature needed is above 1800 deg celcius.