When you put your hands on a cold object, like

Compare the advantages and disadvantages of buying compact fluorescent bulbs rather than filament bulbs (6 marks)

bearhunter [10]

Its 6 blbs of cells containing 6p h2o to creat more cells

7 0

3 years ago

A ray of white light moves through the air and strikes the surface of water in a beaker. The index of refraction of the water is

Naily [24]

Answer:

except ii and iii

Explanation:

The angle of reflection is the angle to the normal the white rays strikes the water surface and it is the incidence angle. Since the white light is moving from less dense medium to a denser medium or a medium with a higher refractive index; the angle of refraction will be less than 30 degrees. Total internal reflection cannot occur because the white light is traveling from a less dense medium to a denser medium.

3 0

3 years ago

A toy rocket moving vertically upward passes by a 2.0-m-high window whose sill is 8.0 m above the ground. The rocket takes 0.15

sveta [45]

Answer:

$v_i = 18.86 m/s$

Explanation:

As we know that the speed of the rocket is v1 and v2 at the bottom and top of the window

then we will have

$d = (\frac{v_1 + v_2}{2}) t$

$2 = (\frac{v_1 + v_2}{2})(0.15)$

$26.67 m/s = v_1 + v_2$

also we know that

$v_2 - v_1 = (-9.81)(t)$

$v_2 - v_1 = (-9.81)(0.15) = -1.47$

now we have

$v_2 = 12.6$

also we have

$v_1 = 14.1 m/s$

now if the sill of the window is at height 8 m from the ground then we have

$v_1^2 - v_i^2 = 2 a h$

$(14.1^2) - v_i^2 = 2(-9.81)(8)$

$v_i = 18.86 m/s$

8 0

3 years ago

Part D- Isolating a Variable with a Coefficient In some cases, neither of the two equations in the system will contain a variabl

Shtirlitz [24]

Answer:

D) D = $\frac{5}{4} - \frac{3}{4} \ C$ , E) (C, D) = ( $\frac{17}{7}, \ \frac{-4}{7}$

Explanation:

Part D) two expressions are indicated

3C + 4D = 5

2C +5 D = 2

let's simplify each expression

3C + 4D = 5

4D = 5 - 3C

we divide by 4

D = $\frac{5}{4} - \frac{3}{4} \ C$

The other expression

2C +5 D = 2

2C = 2 - 5D

C = $1 - \frac{5}{2} \ D$

we can see that the correct result is 1

Part E.

It is asked to solve the problem by the substitution method, we already have

D = $\frac{5}{4} - \frac{3}{4} \ C$

we substitute in the other equation

2C +5 D = 2

2C +5 (5/4 - ¾ C) = 2

we solve

C (2 - 15/4) + 25/4 = 2

-7 / 4 C = 2 - 25/4

-7 / 4 C = -17/4

7C = 17

C = $\frac{17}{7}$

now we calculate D

D = $\frac{5}{4} - \frac{3}{4} \ \frac{17}{7}$

D = 5/4 - 51/28

D = $\frac{35-51}{28}$

D = - 16/28

D = $- \frac{4}{7}$

the result is (C, D) = ( $\frac{17}{7}, \ \frac{-4}{7}$ )

8 0

3 years ago

How many minutes does it take light from the sun to reach earth? (the distance from the sun to earth is 93 million mi; the speed

LenKa [72]

The speed of light is given which is 3*10˄8 = 300,000,000 m/s <span>
93,000 miles = 149,668,992 000 meters - distance from sun to earth
149,668,992,000/300000000 = 498.9 seconds - time for light from sun to reach earth
498.9 seconds/60 seconds per minute = 8.3 minutes - time for light from sun to reach earth </span>

<span>So the answer is approximately 8 minutes.</span>

6 0

3 years ago