A petrol engine consumes 5kg of petrol per hour. if the power of the engine is 20kw and the calorific value of petrol is 11×103kcal per kg . calculate the efficiency of the engine

Suppose a wheel with a tire mounted on it is rotating at the constant rate of 2.15 times a second. a tack is stuck in the tire at a distance of 0.373 m from the rotation axis. noting that for every rotation the tack travels one circumference (a) find the tack's tangential speed. (b) what is the tacks radial acceleration?

Aball of mass 0.3kg is released from rest at a height of 8m.how fast is it going when it hits the ground? accleration due to gravity is g=9.8m/s

What word chemical equation describes cavendish’s experiment with zinc?