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Putting bee honey on a cut kills bacteria. Honey contains a high concentration of sugar. Use your knowledge of water potential to suggest how putting honey on a cut kills bacteria.

Once honey is added to an infected cut, the osmotic gradient favours water moving from the bacterial cells to the honey. This is because the water potential is lower in the honey. As a result of the loss of ...
HM
Answered by Harry M. • Biology tutor
3865 Views

Consider a cone of vertical height H (in metres) and base radius R (in metres) which is full with water. The cone, at time t=0, starts to leak such that it loses water at a rate of k m^3 per second. Give an expression for the rate of change of H.

L = (H 2 +R 2 ) 1/2 V = (1/3)πR 2 (H 2 +R 2 ) 1/2 dV/dt = -k dH/dt = dH/dV × dv/dt dV/dH = (1/3)πR 2 H(H 2 +R 2 ) 1/2 Thus, dH/dt = -3k/(πR 2 H(H 2 +R 2 ) 1/2 ) ​​​​​ ​​​​ ​​
CE
Answered by Callum E. • Maths tutor
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Integrate the following function: f(x) = ln(x)

∫ln(x)dx = xln(x) - ∫x/x dx = xln(x) - x + C
CE
Answered by Callum E. • Maths tutor
3750 Views

Solve the simultaneous equations 3x+5y=7, 2x-3y=11

Multiply the first equation by 2, and the second by 3: 6x+10y=14 6x-9y=33 Subtract the second from the first: 19y=-19 solve for y: y=-1 plug in to first equation and solve for x: 6x+10*(-1)=14 6x=24 x=4
JB
Answered by Jamie B. • Maths tutor
9659 Views

Why is the differential of a constant zero?

Any constant (say k) can be rewritten as kx 0 since x 0 =1. When you differentiate this, the 0 which is the power of the x term gets dragged to the front and is multiplied with the rest of the expression (ac...
JC
Answered by Jawad C. • Maths tutor
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