1). If you want the wheel to turn as one solid piece, then all parts of it must have the same RATE of rotation. If one part was going 2 RPM and another part was going 3 RPM, then there's no way both parts could stay hooked together. Their SPEED depends on their distance from the center, but they all have to make the same RPM. 2). The CENTRIPETAL acceleration of anything that's rotating is. m-v-squared/ R. The object's speed depends on its radius, and it's acceleration varies directly with the square of the speed. So if you move in to half the radius, the acceleration becomes 1/4 of the original value.
Answer:
In physics, a polar vector is a vector such as the radius vector that reverses sign when the coordinate axes are reversed
Explanation:
Polar vectors are the type of vector usually simply known as "vectors." In contrast, pseudovectors (also called axial vectors) do not reverse sign when the coordinate axes are reversed.
Answer;
C.It is the minimum amount of material needed to sustain a fission reaction.
Explanation;
-A critical mass is the smallest or the minimum amount of fissile material needed for a sustained nuclear chain reaction. A critical mass must be achieved in order for the chain reaction to continue and release the atomic energy. A critical mass is needed for both a nuclear reactor and an atomic or hydrogen bomb.
-The critical mass of a fissionable material depends upon its nuclear properties (specifically, the nuclear fission cross section), its density, its shape, its enrichment, its purity, its temperature, and its surroundings.
The formula of density is given by
Density = Mass ÷ Volume
We have:
Mass = 1.989 × 10³⁰ kg
Volume =

=

km³
Density =

=1.13×10¹⁸ kg/km³
Converting 1.13 × 10¹⁸ kg/km³ to g/cm³
1.13 × 10¹⁸ kg = 1.13 × 10¹⁸ × 10³ = 1.13 × 10²¹ grams
1 km³ = 1 × 10⁶ cm³
(1.13 × 10²¹) ÷ 10⁶ = 1.13 × 10¹⁵ gr/cm³
Answer: Density 1.13 × 10¹⁵ gr/cm³