The diameter XY of a circle has length d cm.O is a point on the circumference of this circle such that a new circle with centre O passesthrough points X…

A submarine uses sound of frequency 6000 Hz to locate obstructions ahead of it in the sea. A pulse of this sound reflects off an object that is 750 m…

The compounds BrCl and BrI melt at – 66 °C and 42 °C, respectively. What is the best explanation for this difference in melting points? Answer:

The table below gives some information about the number and biomass of organisms in thefood chain:rose bush → aphid → ladybirdorganism number oforganismsbiomass at eachlevel(arbitrary units)rose bush 1 800aphid 4000…

PQRS is a kite. Points P, Q and R are plotted on the diagram.P is the point (0, 1) and R is the point (4, 5).angle PQR = 90°The point…

A diver of mass 45 kg jumps from a diving board and reaches a maximum height of 10 m above the surface of the water in a swimming pool. Assume…

Propene is an alkene. The structural formula of propene is shown. A polymer can be made from propene. What is the correct structural formula of this polymer? Answer: 18) D…

Six test tubes were set up. Two different solutions were added to each test tube as shown in the table.The temperature, pH and all concentrations were optimal.Which three mixtures would…