All categories

3 years ago

If the radius of a coinis 20cm, find itssurface area -

Physics

1 answer:

meriva3 years ago

8 0

Answer:

800 $\pi$ cm²

Explanation:

Given parameters:

radius of the coin = 20cm

Unknown:

Surface area of the coin = ?

Solution:

A coin is made up of two faces;

Surface area = 2(πr²)

Insert the parameters and solve;

Surface area = 2( $\pi x 20^{2}$ )

Surface area = 800 $\pi$ cm²

You might be interested in

At the local swimming hole, a favorite trick is to run horizontally off a cliff that is 8.0 m above the water. One diver runs of

Alika [10]

Answer:

Number of revolutions=1.532 revolutions

Explanation:

Given data

Distance s=8.0 m

Angular speed a=1.2 rev/s

To find

Number of revolutions

Solution

From the equation of simple motion we not that

$S=ut+1/2gt^{2}\\ where\\u=0\\So\\8.0m=0+(1/2)(9.8m/s^{2} )t^{2}\\ t^{2}=\frac{8.0m}{0.5*9.8m/s^{2} } \\ t^{2}=1.63\\t=\sqrt{1.63} \\t=1.28s$

So for the number of revolutions she makes is given as

$n=a*t\\n=(1.2rev/s)(1.28s)\\n=1.532revolutions$

8 0

3 years ago

Before the start of a trip, air in a tire is at 320 kPa gage pressure and 27°C temperature. At the end of the trip the tire pres

tia_tia [17]

Answer:

The temperature of air in the tire is 55.57 ºC

Explanation:

Please look at the solution in the attached Word file

Download docx

7 0

3 years ago

Each plate of a parallel‑plate capacitor is a square of side 3.63 cm, and the plates are separated by 0.473 mm. The capacitor is

NARA [144]

Answer:

E= 55.53 x 10³ V/m

Explanation:

Given that

a= 3.63 cm

Area ,A= a²

distance ,d= 0.473 mm

Stored energy ,U = 8.49 nJ

Value of capacitor given as

$C=\dfrac{\varepsilon _oA}{d}$

By putting the values

$C=\dfrac{8.85\times 10^{-12}\times 3.63^2\times 10^{-4}}{0.473\times 10^{-3}}$

C=2.46 x 10⁻¹¹ F

$U=\dfrac{1}{2}CV^2$

V=Voltage difference

$V=\sqrt{\dfrac{2U}{C}}$

$V=\sqrt{\dfrac{2\times 8.49\times 10^{-9}}{2.46\times 10^{-11}}}$

V=26.27 V

V= E d

E=Electric filed

26.27 = E x 0.473 x 10⁻³

E= 55.53 x 10³ V/m

7 0

3 years ago

Why the weight of a body decreases with increases in distance from the earth's surface

Tom [10]

because as the distance increases the gravitational force decreases so the weight of a body decreases

6 0

3 years ago

Read 2 more answers

A 70.0 kg skydiver falls towards the earth. If the force due to air resistance is 0 N, what is the acceleration of the skydiver?

lukranit [14]

The gravitational acceleration g = 9.81 m/s²

7 0

3 years ago

Read 2 more answers

If the radius of a coinis 20cm, find itssurface area -​

If the radius of a coinis 20cm, find itssurface area -