Taking the speed of sound in air as 300 m/s and in steel as 4800 m/s. A worker lies next to a railway line and hears the whistle of a…

A sample of an alkali XOH of mass 2.8 g was dissolved in water. This solution was neutralised by 12.5 cm3 of sulphuric acid of concentration 2.0 mol dm-3.2 XOH…

Red-green colour blindness is a condition caused by a recessive allele. The gene is carried on the X chromosome. A man is red-green colour blind, which of his relatives must…

A quadratic equation has solutions a and b.a + b = -5 ab = 3What is the equation? Answer: 24) A (x = a) and (x = b)x – a…

A lorry of mass m, and travelling initially at speed v along a horizontal road, is brought to rest by an average braking force F in time t. Ignoring any…