The air resistance, RR newtons, is directly proportional to the square of the speed, VV m/s, of an object when it is falling.
The air resistance is 24 newtons at a certain speed.
Find the air resistance when the speed is increased by 50%.
Answer ___ newtons 16 workers can tile 2 rooms in 60 hours.
How many workers are needed if 5 rooms are to be tiled in 72 hours?
Answer ___ workers

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Worked solution

19(a)

1. Represent the 50% increase in speed as a scale factor.

A 50% increase means the new speed is
100%+50%=150%=1.5100\%+50\%=150\%=1.5
of the original speed.

2. Apply the square relationship between air resistance and speed.

Since RR is directly proportional to V2V^2,
R∝V2.R \propto V^2.
When VV is multiplied by 1.51.5, V2V^2 is multiplied by
(1.5)2=2.25.(1.5)^2=2.25.

3. Find the new air resistance.

Original air resistance =24=24 N.
New air resistance=24×2.25=54\text{New air resistance}=24\times 2.25=54

Answer

5454 newtons

19(b)

1. Set up the worker scaling using rooms and hours.

For the same tiling rate per worker,
workers∝roomshours.\text{workers} \propto \frac{\text{rooms}}{\text{hours}}.
So
W=16×52×6072.W=16\times \frac{5}{2}\times \frac{60}{72}.

2. Calculate the required number of workers.

W=16×52×6072=16×52×56=2006×5?W=16\times \frac{5}{2}\times \frac{60}{72}=16\times \frac{5}{2}\times \frac{5}{6}=\frac{200}{6}\times 5?
More directly,
W=16×52×6072=16×2.5×56=40×56=1003.W=16\times \frac{5}{2}\times \frac{60}{72}=16\times 2.5\times \frac{5}{6}=40\times \frac{5}{6}=\frac{100}{3}.

Answer

5050 workers

AI analysis — may contain mistakes.

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