Add or subtract as indicated:

A train moving near the speed of light enters a tunnel. According to a person standing in the middle of the tunnel, the back end

Neporo4naja [7]

Answer: The person sitting in the middle of the train sees the back of the train enter ing the tunnel before the front end comes out.

Explanation:

4 0

3 years ago

Can the kinetic energy of an object be negative? Can the potential energy of an object be negative? Can a potential energy funct

IceJOKER [234]

Answer:

Kinetic energy cannot be negative

potential energy is a reference dependent quantity and it can be positive as well as negative both

Since potential energy is defined only for conservative force so it can not be found for friction force

Explanation:

Kinetic energy of an object is given by the formula

$KE = \frac{1}{2}mv^2$

here we know that

m = mass of object that can not be negative

v = speed of the object and since its square is given here so it can not be negative

so Kinetic energy is always positive

potential energy is given as the energy due to the virtue of the position of object

so it is

$\Delta U = -\int F.dr$

so potential energy is a reference dependent quantity and it can be positive as well as negative both

Since potential energy is defined only for conservative force so it can not be found for friction force

5 0

3 years ago

A student has a small metal sphere that hangs from an insulating string. The student, in seeking to determine the charge on the

Leokris [45]

Answer:

the answer the correct one is c

Explanation:

Electric charges of different signs attract and those of the same sign repel. In addition, there are two types of insulating bodies, where the loads are fixed (immobile) and metallic (with mobile loads.

Let's analyze the situation presented

* A rod with positive approaches and the sphere is attracted, so the charge on the sphere is negative

* A rod with a negative charge approaches and the sphere is attracted, therefore the charge of the sphere must be positive.

For this to happen, the sphere must be unloaded and the charge that creates the phenomenon are induced charges because the mobile charges of the same sign as the sphere are repelled.

when checking the answer the correct one is c

8 0

3 years ago

Indiana Jones is in a temple searching for artifacts. He finds a gold sphere with a radius of 2 cm sitting on a pressure sensiti

Vlad1618 [11]

Answer:

Volume of Sand = 0.4 m³

Radius of Sand Sphere = 0.46 m

Explanation:

First we need to find the volume of gold sphere:

Vg = (4/3)πr³

where,

Vg = Volume of gold sphere = ?

r = radius of gold sphere = 2 cm = 0.02 m

Therefore,

Vg = (4/3)π(0.2 m)³

Vg = 0.0335 m³

Now, we find mass of the gold:

ρg = mg/Vg

where,

ρg = density of gold = 19300 kg/m³

mg = mass of gold = ?

Vg = Volume of gold sphere = 0.0335 m³

Therefore,

mg = (19300 kg/m³)(0.0335 m³)

mg = 646.75 kg

Now, the volume of sand required for equivalent mass of gold, will be given by:

ρs = mg/Vs

where,

ρs = density of sand = 1602 kg/m³

mg = mass of gold = 646.75 kg

Vs = Volume of sand = ?

Therefore,

1602 kg/m³ = 646.75 kg/Vs

Vs = (646.75 kg)/(1602 kg/m³)

Now, for the radius of sand sphere to give a volume of 0.4 m³, can be determined from the formula:

Vs = (4/3)πr³

0.4 m³ = (4/3)πr³

r³ = 3(0.4 m³)/4π

r³ = 0.095 m³

r = ∛(0.095 m³)

4 0

3 years ago

During which stage of prophase i does crossing over take place?

Rom4ik [11]

Do you mean mitosis? If so metaphase.

3 0

3 years ago