Answer:
An estimate for the time it will take for a spacecraft to travel from Earth to Mars is approximately 138.8 days
Explanation:
The distance between Earth and the Moon = 684,400 km
The distance between Earth and Mars = 220.58 × 10⁶ km
The distance between Earth and Pluto = 5.2241 × 10⁹ km
The ratio of the distance between Earth and Pluto and the distance between Earth and Mars = (5.2241 × 10⁹ km)/(220.58 × 10⁶ km) ≈ 23.683
It took 2006 to 2015 (9 years) to travel from Earth to Pluto, therefore, it can take approximately (9 years)/(23.683) ≈ 0.38 of a year which is ((9 years)/(23.683)) × 365.2422 ≈ 138.8 days for a spacecraft to travel from Earth to Mars
An electric motor is an electrical machine that converts electrical energy into mechanical energy.
Electric motors work on the principal of the interaction between magnetic field electr-magnetism. A loop which is carrying the current is placed in a magnetic field. The loop will experience a torque. The torque starts rotating the coil and the propellers start to rotate when the current passes through the loop.
Use v = u + at
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Answer:
The value of the average convection coefficient is 20 W/Km².
Explanation:
Given that,
For first object,
Characteristic length = 0.5 m
Surface temperature = 400 K
Atmospheric temperature = 300 K
Velocity = 25 m/s
Air velocity = 5 m/s
Characteristic length of second object = 2.5 m
We have same shape and density of both objects so the reynold number will be same,
We need to calculate the value of the average convection coefficient
Using formula of reynold number for both objects
Here, 
Put the value into the formula
Hence, The value of the average convection coefficient is 20 W/Km².
