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: The work is 1863 N*m
Explanation:
We can define work as:
W = F*d
Where F is the force that the mover needs to apply to the refrigerator, and d is the distance that the refrigerator is moved.
To move the refrigerator, the minimal force that the mover needs to do is exactly the friction force (In this case, the refrigerator will move with constant speed).
Then we will have:
F = 230 N
and the distance is 8.1 meters, then the work will be:
W = 230N*8.1 m = 1863 N*m
Answer:
B = 191.26 cm
θ = -14.73°
Explanation:
given,
magnitude of the first displacement(A) = 146 cm
at an angle of 124°
resultant magnitude = 137 cm
and angle made with x-axis by the resultant(R) = 32.0°
component of A in X and Y direction
A x = A cos θ = 146 cos 120° = -73 cm
A y = A sin θ = 146 sin 120° = 126.4 cm
now component of resultant in x and y direction
R x = 137 cos 35°
= 112.2 cm
R y = 137 sin 35°
= 78.6 cm
resultant is the sum of two vectors
R = A + B
R x = A x + B x
B x = 112.2 - (-73) = 185.2 cm
B y = R y - A y
B y = 78.6 - 126.4 = -47.8 cm
magnitude of B
B = 
B = 
B = 191.26 cm
angle
θ = -14.73°
Answer:296.76 N
Explanation:
Given
mass of box 
Let 
be the Tension in left side and 
be the Tension in the right side
From diagram
and
![T_2\left [ \tan 80\cdot \cos 65+\sin 65\right ]=100\cdot g](https://tex.z-dn.net/?f=T_2%5Cleft%20%5B%20%5Ctan%2080%5Ccdot%20%5Ccos%2065%2B%5Csin%2065%5Cright%20%5D%3D100%5Ccdot%20g)
![T_2=\frac{100\cdot g}{\left [ \tan 80\cdot \cos 65+\sin 65\right ]}](https://tex.z-dn.net/?f=T_2%3D%5Cfrac%7B100%5Ccdot%20g%7D%7B%5Cleft%20%5B%20%5Ctan%2080%5Ccdot%20%5Ccos%2065%2B%5Csin%2065%5Cright%20%5D%7D)
