Answer:
In animations, usually the sizes of the objects are does not appear to be right because they are made to show the basic features and what's generally happening in the above mentioned case. These inaccuracies are consciously made for the better understanding of the audience. So following are the inaccuracies,
B.The astronaut is too big compared to the moon.
D.The moon is too big compared to its orbit.
F.The moon is too big compared to earth.
Vector quantity is defined by direction as well as magnitude both
so now lets discuss all option
1) distance = it is total path length between two points so there is no direction needed in it so it is scalar
2) Speed = it is ratio of total distance covered and total time, so it also do not require any direction.
<em>3)velocity = it is ratio of displacement and time, and displacement is always given with direction so velocity is a vector quantity</em>
4) time = time is the measurement of the interval of two events and we do not require any direction in it so its a scalar quantity.
Answer: C. good reflector of heat
Explanation:
In space, sunlight transfers heat by radiation to objects and bodies and this includes satellites and astronauts. In addition, although the peak of the sun's emission is in the visible region of the electromagnetic spectrum, a part is also emitted in infrared (transferring thermal energy or heat) and ultraviolet (especially in the upper part of the Earth's atmosphere).
That is why in space missions, objects and many satellites are covered by thin layers or sheets that reflect this thermal energy and thus avoid damaging the equipment due to high temperatures.
In this sense, among the reflective materials used are aluminum, silver, copper and gold; the latter being the most used because it does not corrode or oxidize (unlike silver and copper) and is more malleable than aluminum.
On the other hand, <u>astronauts are also vulnerable to the effects of infrared radiation, especially their eyes</u>, since the human eye has no receptors in the infrared spectrum. <u>That is why the astronaut's helmet visor is covered with a thin layer of gold to avoid the dangerous effects of solar radiation.</u>
Density = mass / volume
mass = 1.1 g
volume = length of side ^ 3 = [1.2 * 10^-5 km * 100000 cm/km]^3 = [1.2 cm]^3 = 1.728 cm^3
density = 1.1 g / 1.728 cm^3 = 0.64 g / cm^3
Answer:
Explanation:
Let four particles are placed on X axis symmetrically about the origin and M is placed on y axis.
According to the diagram, the x component of forces balances each other and the net force acting on the particle of mass m is acting in the direction of negative Y axis.