What is reflection? Reflection is light that has struck a surface and has ______

How to solve these two questions?

hammer [34]

1) See attached figure

The relationship between charge and current is:

$i = \frac{Q}{t}$

where

i is the current

Q is the charge

t is the time

Therefore, the current is the rate of change of the charge passing through a given point over time.

This means that for a graph of charge over time, the current is just equal to the slope of the graph.

For the graph in this problem:

- Between t = 0 and t = 2 s, the slope is

$\frac{50-0}{2-0}=25 C/s$

therefore the current is

i = 25 A

- Between t = 2 s and t = 6 s, the slope is

$\frac{-50-(50)}{6-2}=-25 C/s$

therefore the current is

i = -25 A

- Between t = 6 s and t = 8 s, the slope is

$\frac{0-(-50)}{8-6}=25 C/s$

therefore the current is

i = 25 A

The figure attached show these values plotted on a graph.

2) $15 \mu C$

The previous equation can be rewritten as

$Q = i t$

This equation is valid if the current is constant: if the current is not constant, then the total charge is simply equal to the area under a current vs time graph.

Here we have the current vs time graph, so we gave to find the area under it.

The area of the first triangle is:

$A_1 = \frac{1}{2}(0.001 s)(0.010 A)=5\cdot 10^{-6} C$

While the area of the second square is

$A_2 = (0.002 s - 0.001 s)(0.010 A)=1\cdot 10^{-5}C$

So, the total area (and the total charge) is

$Q=A_1 +A_2 = 5\cdot 10^{-6} + 1\cdot 10^{-5} = 1.5\cdot 10^{-5}C=1.5 \mu C$

3 0

4 years ago

How much energy (in kW-h) does a 900 Watt stove use in a week if it is used for 1.5 hours each day?

ioda

Answer:

9.45 kWh

Explanation:

Energy = Power × time

E = 900 W × (1.5 h/day × 7 day)

E = 9450 Wh

E = 9.45 kWh

3 0

3 years ago

Find the angular momentum of a hollow spinning sphere when its angular speed is 20rad/s. The rotational inertia of the sphere is

zysi [14]

Answer:

L= 0.4 kgm²/s

Explanation:

The angular momentum of a hallow spinning sphere is

L = Iω

L = (0.02kgm²) × (20rad/s)

L= 0.4kgm²/s

5 0

3 years ago

What are the answers to #1 and #2?

sergiy2304 [10]

5.0 m (1) (2) the slope of the line at any point in time

4 0

3 years ago

Help me please, i need it fast

s2008m [1.1K]

Answer:

2) C. (x - 3)² + (y + 2)² = 25

5) x² + y² - 8x - 16y + 54 = 0

6) x² + y² - 10x - 12y + 36 = 0

Explanation:

2)

center of circle = 3, -2

x1, y1

end point of circle = 7, 1

x2, y2

the equation of a circle is Pythagorean theorem

x² + y² = r² (where r is the radius of a circle)

distance between points

(x2 - x1)² + (y2 - y1)² = r²

(7 - 3)² + (1 - (-2))² = r²

r² = 25

therefore the equation to the circle is

(x - 3)² + (y + 2)² = 25

=========================================

5)

write the general form of a circle with the center (4,8)

and containing the point (-1, 7)

distance between points

(x2 - x1)² + (y2 - y1)² = r²

(-1 - 4)² + (7 - 8)² = r²

r² = 26

(x - 4)² + (y - 8)² = 26

(x - 4)(x - 4) + (y - 8)(y - 8) = 26

x² - 8x + 16 + y² - 16y + 64 -26 = 0

x² + y² - 8x - 16y + 54 = 0

=========================================

6)

find the general form of a circle with center (5,6)

and tangent to the y-axis.

center (5,6)

h, k

radius = r²

r = 5

(x - h)² + (y - k)² = r²

(x - r)² + (y - k)² = r²

(x - 5)(x - 5) + (y - 6)(y - 6) = r²

x² - 10x + 25 + y² - 12y + 36 = 25

x² + y² - 10x - 12y + 36 = 0

=========================================

8 0

3 years ago

What is reflection? Reflection is light that has struck a surface and has _______.