The diameter of circular disc is 18 cm. Find the area of the disc in terms ...cm²​

1. The diameter of circular disc is 18 cm. Find the area of the disc in terms ...cm²​

Jawab:

Area of the disc = 254,5 cm²

Penjelasan dengan langkah-langkah:

Area of a disc = π × r²

r = 18/2 = 9 cm

Area = π × 81 = 254,5 cm²

2. A planet of mass p moves in a circular orbit of radius r round a sun ....

moving in the sun

semoga bermanfaat

3. A Circular Mirror Has An Area of 616 cm2 The Radius Of The Mirror Is Help​

Jawaban:

radius circular mirror is r = 14 cm

Penjelasan dengan langkah-langkah:

area = π r²

616 = 22/7 x r²

616 ÷ 22/7 = r²

616 x 7/22 = r²

196 = r²

r² = 196

r = √196

r = 14

4. The safe radius, v m/s, at which a train can round a curve of radius r is directly proportional to the square root of r. It is given that the safe speed at which a train can round a curve of radius 256 m is 80 m/s. find the safe speed if the curve has a radius of 225 m.

since safe velocity (v) is directly proportional to the square root of radius (r), so we can conclude that

[tex]

v=c\cdot\sqrt{r}

[/tex]

whereas [tex]c[/tex] is particular constant related to the equation.

Now, by substituing [tex]v=80[/tex] and [tex]r=256[/tex] we will find out the constant [tex]c[/tex]

[tex]

\begin{aligned}

v&=c\cdot\sqrt{r}\\

80&=c\cdot\sqrt{256}\\

80&=c\cdot16\\

\therefore c&=5

\end{aligned}

[/tex]

Now, for [tex]r=225[/tex] m, we have

[tex]\begin{aligned}

v&=c\cdot\sqrt{r}\\

&=5\cdot\sqrt{225}\\

&=5\cdot15\\

&=75

\end{aligned}[/tex]

So, the safe velocity for radius 225 m is 75 m/s

____

5. Mohon bantuannya ya... 1. A disc rotates at a constant angular velocity of 4rad/s. The mass of the disc is 200g and the radius is 4cm. The angular momentum of the disc rotation is... Kg m2/s 2. A 2m-long rope is wound on a wheel shaft. The rope is pulled with the force of 40N. When the rope is released, the wheel rotates at an angular acceleration of 2rad/s2. Assuming that there is no friction, the wheel's moment of inertia is...kg m2

1. 50 Kg m2/s
2. 20 kg m2

6. 1 a) A disc of radius 0.35 m and mass 2.8 kg is free to rotate about its axis which is vertical. A tangential force of 5.0 N is applied to the rim of the disc for 4.0 s. The disc starts to rotate from rest. Calculate (i) the angular acceleration of the disc (ii) the angular displacement in 4.0 s. [Given: Moment of inertia of disc about its axis, I = 1/2mr²]​

Penjelasan:

semoga membantu dan tetap semangat, guys

7. From a circular sheet of radius 4 cm, a circle of 3 cm is removed.Find the area of the remaining sheet.[tex] \sf \: take \: \pi \: as \: 3.14[/tex]- Need Full Explanation in English!​

Given:

From a circular sheet of radius 4 cm, a circle of 3 cm is removed.

ToFind:

the area of the remaining sheet.

Solution:

Weknowthat,

➼ Area of a circle = πr²

Now,

➱Area removed = πR² - πr²

➱ Area removed = 3.14 × 4× 4 - 3.14 × 3 × 3

➱ Area removed = 50.24 - 28.26

➱ Area removed = 21.98cm²

Henceforth21.98cm²ofareaisremoved

Given-

From a circular sheet of radius (R) 4 cm, a circle of radius (r) 3 cm is removed.

Tocalculate-

The area of the remaining sheet

Solution-

‎ ‎ ‎ ‎ ‎Since a circular part is removed from the total area of the sheet, here forms the expression:

★ Area of circular sheet – Area of circular part removed

[tex]\: \: \: \: \underline{ \boxed{ \sf \pmb{Area_{(circle)} = \pi {r}^{2} \: sq.units }}}[/tex]

On solving the expression,

[tex] \dashrightarrow { \sf{(\pi {R}^{2}) - (\pi {r}^{2}) }} \\ \\ \dashrightarrow { \sf{\pi( {R}^{2} - {r}^{2} )}} \\ \\ \dashrightarrow { \sf{\pi( {4}^{2} - {3}^{2} )}} \\ \\ \dashrightarrow { \sf{\pi(16 - 9)}} \\ \\ \dashrightarrow { \sf{\pi(7)}} \\ \\ \dashrightarrow { \sf{ 3.14 \times {7} }} \\ \\ \dashrightarrow \underline{ \boxed{ \sf \pmb{ \red{21.98 \: {cm}^{2} }}}}[/tex]

Required answer-

The area of the remaining sheet is 21.98cm².______________________________________________

8. 1. The volume of a cone with a circular base of radius 8 cm is 320π cm³. Find its height.​

Jawaban:

4

Penjelasan dengan langkah-langkah:

circular base of radius 8cm is 320

320/8=4 cm

9. A solid metal sphere of surface area 394,24 cm2 is melted down and recast as a solid circular cone of height 5.6 cm. find the base radius of the cone.

Jawaban:

the working and the answer are shown in the pic.

semangat belajar....

10. A sphere of conductor with radius R has a spherical hole of radius D measuredfrom the center of the sphere, with D> R/2. At the center of the conductor sphereis placed a point charge + Q. If k = 1 and co is the electric permittivity of air, thenthe magnitude of the electric field at a point of R/2 from the center of theconductor sphere is....a. 4kQ/R^2b. kQ/(R+a)^2c. kQ/R^2d. 0e. 8kQ/R^2​

Sebuah bola konduktor berjari-jari R memiliki lubang berbentuk bola berjari-jari D yang diukur

dari pusat bola, dengan D> R / 2. Di tengah bidang konduktor pusat bidang konduktor

ditempatkan muatan titik + Q. Jika k = 1 dan co adalah permitivitas listrik udara, maka

besarnya medan listrik pada titik R / 2dari tengah

lingkungan konduktor adalah ....

Sebuah.

a. 4kQ / R ^ 2

b. kQ / (R + a) ^ 2

c. kQ / R ^ 2

d. 0

e. 8kQ / R ^ 2

Penjelasan dengan langkah-langkah:

itu terjemahan Nya semoga bermanfaat

11. A cone has a circular base of radius 8 cm and height of 17 cm. Find the volume of the cone.

r = 8 cm
t = 17 cm

Volume
= 1/3 . π. r². t
= 1/3 . 3,14 . 8² . 17
= 1/3 . 3,14 . 64 . 17
= 1.138,77 cm³

12. The volume of a cone with a circular base of radius 6 m is 84πm3. find it's height.

itu ya maaf kalo salah

13. The volume of a cylindrical disc is 150 cm3. If the thickness of the disc is 2 cm, find the base radius of the disc. Give your answer correct to 3 significant figures.Tolong dong bsk ulangan :')​

Jawaban:

kayaknya 734cm

Penjelasan dengan langkah-langkah:

maaf kalo salah ya

14. A solid cone has a circular top of radius 5 cm and a slant height of 8 cm. Calculate its total surface area​

Jawaban:

[tex]23 \frac{5}{7} \: {cm}^{2} [/tex]

Penjelasan dengan langkah-langkah:

[tex]lp \: kerucut \: = \: \pi r \: ( \: r + s) \\ \\ = \: \frac{22}{7} \times ( \: 5 \: {cm}^{2} + \: 8 \: {cm}^{2} ) \: \\ \\ = 23 \: \frac{5}{7} \: {cm}^{2} [/tex]

maaf kalo salah :')

15. A cone has a circular base of radius 9 cm and a slant height of 5 cm. find the total surface area of the cone.

Volume = πr²t/3
= 3,14 x 9² x 5/3
= 3,14 x 27 x 5
= 3,14 x 135
= 423,9 cm³

16. The volume of a cone with a circular base of radius 8 cm is 3207 cm. Find its height.

Penjelasan dengan langkah-langkah:

V = ⅓πr²t

t = (3 x 3207)/(3,14 x 8²)

t = 9.621/200,96

t = 47⅞ cm

17. the area of a circle of radius 49 cm is​

Penjelasan dengan langkah-langkah:

dik: r = 49 cm

dit: luas lingkaran

luas lingkaran = π × r × r

= 22/7 × 49 × 49

= 7.546 cm2

semoga membantu :)

18. The gravitational force of a satellite on the surface of the Earth of radius R is F. What is the gravitational force on the satellite when its height is R above the Earth?​

Jawaban:

F/4

Penjelasan:

h = distance from earth core to satellite

h = R+R = 2R

Fb = gravitational force on the satellite when its height is R above the Earth

F = G m / R^2

Fb = GM m / (2R)2

Fb = GM m / 4R2

Fb = (GM m / R2) / 4

Fb = F/4

19. If the angular velocity of a circular motion is w,its frequency is...Hz

KINEMATIKA

• Gerak Melingkar

ω = w

f = __?

ω = 2π f

w = 2π f

f = w / (2π) Hz ✔️

20. A circular gold bangle has an inside radius of 35mm. What is the circumference of the inside of the bangle? Use (22/7) as an approximation for phi

22/7 times 70 = 220cm

the circumfrence is 220cmFormula of circumference is = 2 multiplied phi multiplied radius

Circumference the inside of bangle = 2 multiplied 22/7 multiplied 35 mm
Circumference the inside of bangle = 220 mm

I'm Sorry, i just can understand a little english