<em>Another key factor that determines a star's colour is its temperature. As stars become hotter, the overall radiated energy increases, and the peak of the curve changes to shorter wavelengths. To put it another way, when a star heats up, the light it produces moves toward the blue end of the spectrum.</em>
Answer:
See the answers below.
Explanation:
We will solve this problem by calculating each part separately.
A 500 W hair dyer is used to dry hair for 6 minutes a day for 3 days.
Energy can be calculated by multiplying the value of the power of the equipment by the amount of time of use.
![500 [W]*[\frac{6min}{1day} ]*[\frac{1day}{24hr} ]*[\frac{1hr}{60min} ]=2.083 [W]](https://tex.z-dn.net/?f=500%20%5BW%5D%2A%5B%5Cfrac%7B6min%7D%7B1day%7D%20%5D%2A%5B%5Cfrac%7B1day%7D%7B24hr%7D%20%5D%2A%5B%5Cfrac%7B1hr%7D%7B60min%7D%20%5D%3D2.083%20%5BW%5D)
The cots of electricity is 5.6 cents per kWh. How much would it cost to operate the laptop for 24 hours a day for one week?
We know that the power of the latop is 75 [W], then we can calculate the cost, multiplying the value of the power by the value of the cost by the time of use of the computer.
![0.075[kW]*5.6[\frac{cents}{kw*h}}]*[\frac{24hr}{1day}]*[1week]*[\frac{7days}{1week} ]=70.56 [cents]](https://tex.z-dn.net/?f=0.075%5BkW%5D%2A5.6%5B%5Cfrac%7Bcents%7D%7Bkw%2Ah%7D%7D%5D%2A%5B%5Cfrac%7B24hr%7D%7B1day%7D%5D%2A%5B1week%5D%2A%5B%5Cfrac%7B7days%7D%7B1week%7D%20%5D%3D70.56%20%5Bcents%5D)
A toaster oven is 85% efficient. It uses 1200 J of energy. How much thermal energy is it producing?
Efficiency is defined as the relationship between the energy obtained on the energy delivered. Almost always the energy delivered is greater than the energy obtained (first law of thermodynamics).
Therefore.
![Effic = E_{obtained}/E_{delivered}\\0.85=E_{obtained}/1200\\E_{obtained}=1020[J]](https://tex.z-dn.net/?f=Effic%20%3D%20E_%7Bobtained%7D%2FE_%7Bdelivered%7D%5C%5C0.85%3DE_%7Bobtained%7D%2F1200%5C%5CE_%7Bobtained%7D%3D1020%5BJ%5D)
Answer:
N = 337.96 N
Explanation:
∅ = 32º
F = 249 N
m = 21 Kg
N = ?
We can apply:
∑ F = 0 (↑)
- Fy - W + N = 0 ⇒ N = Fy + W
⇒ F*Sin ∅ + m*g = N
⇒ N = (249 N*Sin32º) + (21 Kg*9.81 m/s²)
⇒ N = 337.96 N (↑)
Answer:
D
Explanation:
We know the formula for Work to be:
W = f * d
Where W is work done
f is force
d is the distance
A)
Work = 50
Distance = 50
So, Force is:
Force = 50/50 = 1
B)
Work = 400
Distance = 80
Force = 400/80 = 5
C)
Work = 365
Distance = 73
Force = 365/73 = 5
D)
Work = 144
Distance = 16
Force = 144/16 = 9
Hence, D is the situation in which the force applied is the greatest.
When a ball is whirled using a string, it is restricted to move only in circular motion because the net force acting on the ball is towards the center of the circle. Hence, the acceleration of the ball is towards the center. But the velocity of ball is tangential to this circular path all the time. When the whirling is stropped, the string becomes slack and tension in the string becomes zero. The ball no more performs circular motion and the ball moves tangentially to the circle in straight line. Therefore, before letting go, velocity was variable. After letting go, velocity becomes constant.
