If the mass of block B is 2kg, the gravitational force exerted on block B is most nearly which of the following? 0.2N
2N
20N

P. S The acceleration is 10m/s^2 but I have no idea how to get that, so could someone explain that to me.

Gravitational force exerted on block B is 20 N

Given that;

Mass of block = 2 kg

Acceleration = 10 m/s²

Find:

Gravitational force exerted on block B

Computation:

Gravitational force = ma

Gravitational force exerted on block B = Mass of block × Acceleration

Gravitational force exerted on block B = 2 × 10

Gravitational force exerted on block B = 20 N

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20 N.

Explanation:

The following data were obtained from the question:

Mass of block B (m) = 2 Kg

Acceleration due to gravity (g) = 10 m/s²

Gravitational force (F) =..?

Force is simply defined as the product of mass and acceleration i.e

Force = mass (m) × acceleration (a)

F = ma

Thus, we can say that the gravitational force on block B will be the product of the mass of block B and acceleration due to gravity i.e

Gravitational force (F) = mass of block B (m) × acceleration due to gravity (g)

F = mg

Mass of block B (m) = 2 Kg

Acceleration due to gravity (g) = 10 m/s²

Gravitational force (F) =..?

F = mg

F = 2 × 10

F = 20 N

The, the gravitational force exerted on block B is 20 N

electromagnetic shielding is the practice of reducing the electromagnetic field in a space by blocking the field with barriers made of conductive or magnetic materials. shielding is typically applied to enclosures to isolate electrical devices from their surroundings, and to cables to isolate wires from the environment through which the cable runs. electromagnetic shielding that blocks radio frequency electromagnetic radiation is also known as rf shielding.

the shielding can reduce the coupling of radio waves, electromagnetic fields and electrostatic fields. a conductive enclosure used to block electrostatic fields is also known as a faraday cage. the amount of reduction depends very much upon the material used, its thickness, the size of the shielded volume and the frequency of the fields of interest and the size, shape and orientation of apertures in a shield to an incident electromagnetic

from wikipedia

there are no contact forces mentioned on the list of choices that you've provided.