A5.10-kg watermelon is dropped from rest from the roof of a 24.0-m -tall building and feels no appreciable air resistance.
calculate the work done by gravity on the watermelon during its displacement from the roof to the ground.
part a
calculate the work done by gravity on the watermelon during its displacement from the roof to the ground.
part bjust before it strikes the ground, what is the watermelon's kinetic energy?
part cjust before it strikes the ground, what is the watermelon's speed?
part dwould the answer in part a be different if there were appreciable air resistance?

Part a)

Part B)

Part C)

Part D)

no change in answer of part A) if there is air resistance in that problem.

Explanation:

Part A)

Work done by the gravity is given as

now we have

m = 5.10 kg

H = 24 m

now we will have

Part B)

As per work energy theorem we can say that work done by all forces = change in kinetic energy of the system

So we will have

Part C)

Now we know that the kinetic energy is given as

Part D)

Work done by gravity only depends on force due to gravity and its displacement so there will be no change in answer of part A) if there is air resistance in that problem.

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

the answer is false. this is because for ice to melt, it requires latent heat of melting. latent heat means heat energy required to change phase without any increase in temperatures. therefore, the ice will take energy from the environment to melt hence atmospheric temperatures will reduce.