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Show, using the focus-directrix property for an ellipse, that PS +PS'=2a where P is a point on the ellipse and S and S' are the two foci.

The focus diretrix property for an ellipse is PS/PD=e. Now this is also the case for the other directrix and focus, so PS'/PD'=e. Now we can rearrange these equations to find a formula for PS +PS', PS +PS'=e...
DL
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A phone is knocked off a table 800cm of the ground. If the phone is 650g a) what is the gravational potential of the phone? b)what speed will the phone hit the floor at? c)How long will it take for the phone to hit the floor?

UNITS - SI UNITS: 800cm --> 0.8m 0.65kg a) Ep= mg(change) height Ep=0.65kg * 9.81m/s 2 * 0.80m Ep=5.10 Joules (J) b) Gravational Potential = Kinetic energy Ek = 1/2 mv 2 v=Sqrt(Ep/0.5m) v=sqrt(5.10/0.5*0....
JJ
Answered by Julia J. • Physics tutor
2058 Views

Name a product of photosynthesis?

Glucose Oxygen
OE
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Find the exact solutions for 4 − x^2 = |2x − 1|

x=-1 x=-1+6 0.5
SV
Answered by Shroya V. • Maths tutor
6225 Views

What is Pythagoras' Theory?

Pythagoras' Theory explains that the length of sides in a right angled triangle are related. This means we can use the length of two sides to find that of the third! The relationship he found is a 2 + b 2 = ...
AR
Answered by Alexander R. • Maths tutor
4546 Views