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3 years ago

If the diameter of a circle changes from 18 cm to 6 cm, how will the circumference change?

1 answer:

6 0

We know that

the length of a circumference=2*pi*r
for D1=18 cm--------------> r1=9cm
L1=2pi*9-------> 18pi cm

for D2=6 cm-----------> r2=3 cm
L2=2pi*3-------> 6pi cm

L2/L1----------> (6pi)/(18pi)---->1/3

the answer is the option A) multiplies by 1/3

You might be interested in

Work out the percentage change when a price of £40 is increased to £70.

Stella [2.4K]

Answer:

75%

Step-by-step explanation:

70-40 = 30

30/40 = 0.75

0.75 = 75%

6 0

3 years ago

A force of 12 lb is required to hold a spring stretched 8 in. beyond its natural length. How much work W is done in stretching i

sattari [20]

Answer:

Work done in stretching the spring = 7.56 lb-ft.

Step-by-step explanation:

Normal length of the spring = 8 in or $\frac{8}{12}$ ft

= $\frac{2}{3}$ ft

If the spring has been stretched to 11 inch then the stretched length of the spring is = 11 in

= $\frac{11}{12}$ ft

Force applied to stretch the spring = 12 lb

By Hook's law,

F = kx [where k is the spring constant and x = length by which the spring is stretched]

12 = k( $\frac{2}{3}$ )

k = 18

Work done (W) to stretch the spring by $\frac{11}{12}$ ft will be

W = $\int\limits^\frac{11}{12} _0 {kx} \, dx$

= $\int\limits^\frac{11}{12} _0 {(18x)} \, dx$

= $18[\frac{x^{2}}{2}]^{\frac{11}{12}}_0$

= 9( $\frac{11}{12}$ )²

= 7.56 lb-ft

6 0

3 years ago

Joel has been offered sales positions at two different companies. Alphaco offers an annual salary of $65,000. OmegaCo offers an

Papessa [141]

The correct answer is B

5 0

2 years ago

Cedric and Insha solved the same equation using the calculations below.

Mariulka [41]

The first working out is correct, z = 3

3 0

3 years ago

A stretched spring has a length of 12 inches when a weight of 2 lbs is attached to the spring. The same spring has a length of 1

Advocard [28]

The way I figured this one out was saying that if it takes 2lbs to stretch it to 12 inches and 5lbs to stretch to 18 inches that means that 3 additional pounds = 6 inches. Therefore, each additional pound is 2 inches. We know already that with 2 lbs it was 12 inches in length and we can also say that 2 lbs = 4 inches. So subtract 4 from 12 and you end up with the answer of 8 inches.

8 0

3 years ago