Answer:
Concrete absorbs visible light and re-radiates it as infrared energy.
Explanation:
As we know that concrete will not reflect 100% light incident on it but it will absorb few energy and remaining energy is reflected back.
So here when visible light incident on the concrete then few of its energy is absorbed by is and then the remaining energy is reflected back.
Since the reflected energy must be less than the energy which incident on the concrete so here we will say that the reflected waves must be of less frequency range
so here most appropriate energy range of reflected wave is infrared waves
so here correct answer will be
Concrete absorbs visible light and re-radiates it as infrared energy.
Answer:
91.5 m/s
Explanation:
m = mass of clay = 12 g = 0.012 kg
M = mass of wooden block = 100 g = 0.1 kg
d = distance traveled by the combination before coming to rest = 7.5 m
μ = Coefficient of friction = 0.65
V = speed of the combination of clay and lock just after collision
V' = final speed of the combination after coming to rest = 0 m/s
acceleration caused due to friction is given as
a = - μ g
a = - (0.65) (9.8)
a = - 6.37 m/s²
Using the kinematics equation
V'² = V² + 2 a d
0² = V² + 2(- 6.37) (7.5)
V = 9.8 m/s²
v = speed of clay just before collision
Using conservation of momentum
m v = (m + M) V
(0.012) v = (0.012 + 0.100) (9.8)
v = 91.5 m/s
Answer:
You could try finding a familiar peer to join the activity with your child. Or ask your child who their friends are at school, or what they look for in a friend at school.
Answer: 0.1524 km
Explanation:
We have to convert 
to kilometers, and we can do it knowing 
and 
:
Hence:
Answer:
Explanation:
Solution:
- We are to develop a circuit that has an input of available battery 9.0 V and has an output potential difference of 3.0 V
- We are given:
Battery ..... 9.0 V
Resistors ... 10 Kohms
- We will develop a potential divider circuit by placing a few resistors in series and then connecting in between resistors to get our desired voltage.
- How many resistors should we use ?
We know that if we add series resistance in a circuit the current decreases proportionally. However, the potential difference across resistors also changes.
- Our desired voltage is a ratio of input battery voltage.
Input / Output = 9 / 3 = 3
We can use this ratio as the number of "Identical resistors" that can be placed in series to give us the desired voltage. Note: This would not be true if we did not had any identical resistors.
- We will place 3, 10 Kohms resistors in series.
- To verify we will calculate the potential difference across each resistor. The current of the total circuit is:
I = V / R_eq
R_eq = 3*R = 30 kohms
I = 9 / 30,000 = 0.0003 Amps
- Now the potential difference for each resistor:
V = I*R_each
V = 0.0003*(10,000)
V = 3.0 V
- We can take two leads across any 10 kohms resistor and the potential difference across the leads would be the desired voltage 3.0 V.
