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a boat is in a still lake with its anchor up in the boat, it then drops its anchor till it hits the bottom of the lake. Is the water level highest a) when the anchor is in the water. b) when the anchor is in the boat. c) it makes no difference.

b) when the anchor is in the lake it displaces the amount of water equivallent to the volume of the anchor, when the anchor is in the boat it displaces the amount of water equivallent to the anchors mass....

Answered by Benjamin C. • PAT tutor

1463 Views

The number of bacteria present in a culture at time t hours is modeled by the continuous variable N and the relationship N = 2000e^kt, where k is a constant. Given that when t = 3, N = 18 000, find (a) the value of k to 3 significant figures

putting in the conditions: 18000 = 2000e^3k .. ln(9) = 3k .. k=(1/3)ln(9)

Answered by Benjamin C. • Maths tutor

4759 Views

A speaker emits a sound wave through a metallic block, with a speed of 0.42 km/s, and a frequency of 16kHz. Calculate the wavelength to 3.s.f. Describe the characteristics of a longitudinal wave.

Firstly the values should be converted into more comfortable units. 0.42km/s = 420m/s, and 16kHz = 16,000Hz. Next, use the equation wavelength = speed/frequency This gives wavelength = 420m/s over 16,000/...

Answered by Joseph B. • Physics tutor

3540 Views

A circle has the equation x^2 + y^2 - 4x + 10y - 115 = 0. Express the equation in the form (x - a)^2 + (y - b)^2 = k, and find the centre and radius of the circle.

Rearrange the equation so that the x terms and y terms bracketed together, like so: (x^2 - 4x) + (y^2 + 10y) - 115 = 0. Complete the square on both sets of brackets, giving (x - 2)^2 - 4 + (y + 5)^2 - 25 ...

Answered by Joseph B. • Maths tutor

3445 Views

When do I use the preterite and when do I use the imperfect?

If you imagine a timeline (would draw out a line on the whiteboard here), the imperfect appears at some extended period over this. It is important to remember that the imperfect encompasses the ideas: som...

Answered by Paddy S. • Spanish tutor

1607 Views