Answer:
F = 51.3°
Explanation:
The component of weight parallel to the inclined plane must be responsible for the rolling back motion of the car. Hence, the force required to be applied by the child must also be equal to that component of weight:
where,
W = Weight of Wagon = 150 N
θ = Angle of Inclinition = 20°
Therefore,
<u>F = 51.3°</u>
Answer:
Temperature decreases because the number of collision of the molecules decreases as they escape or evaporate. Molecules are in constant motion. Increase in temperature leads to increase in average kinetic energy of the molecules.
Answer: independent variable: Size of the feather.
Explanation:
In an experiment, the manipulated/independent variable is, as the name implies, the variable that the scientist can control.
In this case, the scientist has only one variable that he can control at will, and this is the size of the feather (he can choose which feather he uses for the experiment)
So the manipulated variable will be the size of the feather.
And the dependent variable is the one that "answers" to the changes in the manipulated variable.
In this case, will be the time that it takes to the feather to fall to the ground.
Answer: 
Explanation:
Given
Mass of the elevator is 
Time period of ascension 
cruising speed 
Distance moved by elevator during this time
Suppose Elevator starts from rest
Distance moved
Gain in Potential Energy is
Average power during this period is
A "screen" or even just a set of parallel bars are highly reflective to electromagnetic waves as long as the open spaces are small compared to the wavelengths.
"Grid" dishes work fine ... with less weight and less wind resistance ... for frequencies below about 3 GHz. (Wavelengths of at least 10 cm.)
(I even worked on a microwave system in South America where huge grid dishes were used on a 90-mile link.)
