1, their atoms have the same number of valence electron. because valence electron determine the group of elements.

6 0

3 years ago

The intensity of light from a star varies inversely as the square of the distance. If you lived on a planet ten times farther aw

frosja888 [35]

Answer:

the intensity of the sun on the other planet is a hundredth of that of the intensity of the sun on earth.

That is,

Intensity of sun on the other planet, Iₒ = (intensity of the sun on earth, Iₑ)/100

Explanation:

Let the intensity of light be represented by I

Let the distance of the star be d

I ∝ (1/d²)

I = k/d²

For the earth,

Iₑ = k/dₑ²

k = Iₑdₑ²

For the other planet, let intensity be Iₒ and distance be dₒ

Iₒ = k/dₒ²

But dₒ = 10dₑ

Iₒ = k/(10dₑ)²

Iₒ = k/100dₑ²

But k = Iₑdₑ²

Iₒ = Iₑdₑ²/100dₑ² = Iₑ/100

Iₒ = Iₑ/100

Meaning the intensity of the sun on the other planet is a hundredth of that of the intensity on earth.

3 0

4 years ago

The Burj Khalifa in Dubai is the world's tallest building. The structure is 828 m (2,716.5 feet) and has more than 160 stories.

Elena L [17]

Answer:

h = 599.5 m

Explanation:

Given,

height of structure = 828 m

weight of the tourist = 184 lb

= 184 x 0.45359 = 83.43 Kg

Potential energy = 187000 J

PE = m gd

$d = \frac{PE}{mg}$

$d = \frac{187000}{83.43\times 9.81}$

h = 228.5 m

Height of the room above the ground.

h = 828 - 228.5

h = 599.5 m

Height of the floor above ground is equal to 599.5 m.

4 0

3 years ago

A 240 g toy car is placed on a narrow 60-cm-diameter track with wheel grooves that keep the car going in a circle. The 1.0 kg tr

lesya [120]

Answer:

The track's angular velocity is W2 = 4.15 in rpm

Explanation:

Momentum angular can be find

I = m*r^2

P = I*W

So to use the conservation

P1 + P2 = 0

I1*W1 + I2*W2 = 0

Solve to w2 to find the angular velocity

0.240kg*0.30m^2*0.79m/s=-1kg*0.30m^2*W2

W2 = 0.435 rad/s

W2 = 4.15 rpm

8 0

3 years ago