Search our library of homework questions

Top answers

All subjects

All levels

Describe one chemical test and one physical test for pure water.

A physical test for pure water is testing the boiling or freezing point. Pure water will boil at 100 degrees Celsius and freeze at 0 degrees Celsius. One chemical test is to use cobalt chloride paper - th...

Answered by Sumrah N. • Chemistry tutor

40101 Views

Describe the sequence of events that occur during DNA replication.

DNA replication begins with the unzipping of the double stranded DNA by the enzyme DNA helicase, which breaks hydrogen bonds as it separates the strands. Another enzyme known as topoisomerase holds the tw...

Answered by Sumrah N. • Biology tutor

23147 Views

Find the coefficient of x^4 in the expansion of: x(2x^2 - 3x + 1)(3x^2 + x - 4)

Only the terms which will form the x⁴ term need to be considered:x * 2x² * x + x * -3x * 3x² = -7x⁴Therefore the answer is -7.

Answered by Finn H. • Maths tutor

4689 Views

An object of mass 3kg is held at rest on a rough plane. The plane is inclined at 30º to the horizontal and has a coefficient of friction of 0.2. The object is released, what acceleration does the object move with?

We need to use Newtons law F=ma going down the slope.
We can see that the only forces acting in this direction are the component of the weight and friction, so we have that: F = Wsin30 - μR = 3a

Answered by Asha D. • Maths tutor

3372 Views

Describe how a stationary wave is formed at a boundary?

A stationary wave is a wave formed by the superposition of two progressive waves. These waves must have equal amplitude frequency and speed. They must also be travelling in opposite directions. When a wav...

Answered by Oliver E. • Physics tutor

5499 Views