Interactive practice questions
The period of a pendulum varies directly with the square root of its length.
If the length is quadrupled, what happens to the period?
It increases by a factor of $8$8
A
It becomes a quarter of what it was
B
It is doubled
C
It is quadrupled
D
Easy
< 1min
In the equation $y=3x$y=3x, $y$y varies directly as $x$x. When $x=5$x=5, $y=15$y=15.
Easy
1min
Suppose that $p$p varies proportionately to both $q$q and the square of $r$r, and that $p=648$p=648 when $q=30$q=30 and $r=6$r=6.
Easy
3min
The mass in grams, $M$M, of a cube of cork varies directly with the cube of the side length in centimetres, $x$x. If a cubic centimetre of cork has a mass of $0.29$0.29:
Medium
4min
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