Time is precious but we do not know yet how precious

Time is precious, but we do not know yet how precious it really is. We will only know when we are no longe r able to take advantage of it…
iii) z varies directly as the square of x and inversely with the square root of y.. So
2 2
y
kx
z
y
x
z   
Example 1 The law of universal gravitation states that the gravitational force F (in newtons)
between two objects varies jointly with their masses m
1
and m
2
(in kilograms) and inversely
with the square of the distance d (in meters)
between the two objects. The constant of
variation is denoted by G and is called the
universal gravitational constant. Write an
equation for the law of universal gravitation
hence estimate the universal gravitational
constant. Use the Earth and sun facts given
at the right

4) Write an equation for the given relationship.
a) x varies inversely with y and directly with z.
b) y varies jointly with z and the square root of x.
c) w varies inversely with x and jointly with y and z.
5) The variable z varies jointly with x and y. Use the given values to write an equation relating
x, y, and z. Then find z when x =-4 and y = 7. (a) X=3, y=8. Z=6 (b) X=-12, y=4, z=2 (c)
? = =
Exercise
1) Tell whether x and y show direct variation, inverse variation, or neither
?
(e)
d) x y
1.6 40
4 16
5 12.8
20 3.2