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The speed at which a light aircraft can take off is 120 km/h. (A) What is the minimum constant acceleration required for the pla

kondor19780726 [428]

Answer:

A) a = 2.31[m/s^2]; B) t = 14.4 [s]

Explanation:

We can solve this problem using the kinematic equations, but firts we must identify the data:

Vf= final velocity = take off velocity = 120[km/h]

Vi= initial velocity = 0, because the plane starts to move from the rest.

dx= distance to run = 240 [m]

$v_{f} ^{2} =v_{i} ^{2}+2*g*dx\\where:\\v_{f}=120[\frac{km}{h} ]*\frac{1hr}{3600sg} * \frac{1000m}{1km} =33.33[m/s]\\\\Replacing\\33.33^{2}=0+2*a*(240)\\ a=\frac{11108.88}{2*240}\\ a=2.31[m/s^2]\\$

To find the time we must use another kinematic equation.

$v_{f} =v_{i} +a*t\\replacing:\\33.33=0+(2.31*t)\\t=\frac{33.33}{2.31}\\ t=14.4[s]$

7 0

3 years ago

A dog sledding team is composed of a 82.8 kg musher (the person driving the sled), a 21.4 kg sled, and four dogs. Assume that ea

vlabodo [156]

Answer: 340.8W

Explanation: Please see the attachments below

6 0

3 years ago

Read 2 more answers

Copper is a metal commonly used for electrical wiring in houses. Which metal conducts electricity better than copper at 20°C?

jek_recluse [69]

The correct answer is silver metal.
Conductivity measures the ability of a material or a metal to transmit energy, conductivity may be electrical, thermal or acoustical conductivity. The most electrical conductive element is silver, followed by copper and Gold. Silver also has the highest thermal conductivity as compare to any element. However, copper and Gold are more often used in electrical applications since copper is less expensive and gold has a much higher corrosion resistance.

6 0

3 years ago

A 500 W hair dyer is used to dry hair for 6 minutes a day for 3 days. How much energy is used? A laptop uses 75 W. The cot of el

zzz [600]

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.

$500 [W]*[\frac{6min}{1day} ]*[\frac{1day}{24hr} ]*[\frac{1hr}{60min} ]=2.083 [W]$

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.

$0.075[kW]*5.6[\frac{cents}{kw*h}}]*[\frac{24hr}{1day}]*[1week]*[\frac{7days}{1week} ]=70.56 [cents]$

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.

$Effic = E_{obtained}/E_{delivered}\\0.85=E_{obtained}/1200\\E_{obtained}=1020[J]$

4 0

3 years ago

A 235.0 g metal block absorbs 2.44 × 103 J of heat to raise its temperature by 35 K. What is the specific heat of the metal? Sho

andrew-mc [135]

When an object absorbs an amount of energy equal to Q, its temperature raises by $\Delta T$ following the formula
$Q=m C_s \Delta T$
where m is the mass of the object and $C_s$ is the specific heat capacity of the material.

In our problem, we have $Q=2.44 \cdot 10^3 J$ , $m=235.0 g$ and $\Delta T=35 K$ , so we can re-arrange the formula and substitute the numbers to find the specific heat capacity of the metal:
$C_s = \frac{Q}{m \Delta T}= \frac{2.44 \cdot 10^3 J}{(235.0 g)(35 K)}=0.297 J g^{-1} K^{-1}$

3 0

3 years ago