What is electromagnetic radiation?


Answer 1

In short: Electromagnetic radiation is energy that is propagated in the form of electromagnetic waves

Best example of electromagnetic radiation is sunlight. Vsible light of sunlight is only a small portion of the EM spectrum. EM radiation is a form of energy that takes many forms, f.e.: microwaves, radiowaves, etc.

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A block of lead with dimensions 2.0 dm x 8.0 cm x 35 mm, has a mass of 6.356 kg. calculate the density of lead in g/cm


First, let us calculate for the volume of the block of lead using the formula:

V = l * w * h

But we have to convert all units in terms of cm:

l = 2.0 dm = 20 cm

w = 8 cm

h = 3.5 cm


Therefore the volume is:

V = (20 cm) * (8 cm) * (3.5 cm)
V = 560 cm^3


Next we convert the mass in terms of g:

m = 6.356 kg = 6356 g


Density is mass over volume, so:

density = 6356 g / 560 cm^3

density = 11.35 g / cm^3     (ANSWER)


How many joules are needed each day


I believe the answer is 4,200 Joules each day
The amount of joules needed to preform work depends on the force and distance there is no set amount of joules per day.

What does latitude measure


It is the distance of a place north or south of the earth's equator. It's expressed in minutes or degrees
It's used to measure the north or south distance of how far a certain place is located.

If two solutions have unequal concentrations of a solute, the solution with the lower concentration is called


Obviouskly lower concentrstion


If an object is propelled upward from a height of 128 feet at an initial velocity of 112 feet per​ second, then its height h after t seconds is given by the equation h equals negative 16 t squared plus 112 t plus 128. After how many seconds does the object hit the​ ground? Round to the nearest tenth of a second.



The equation of motion of an object is given by :


t is the time in seconds

We need to find the time when the object hits the ground. When the object hits the ground, h(t) = 0


On solving above equation using online calculator, t = 8 seconds. So, the object hit the ground after 8 seconds. Hence, this is the required solution.


Two blocks, joined by a string, have masses of 6.0 and 9.0 kg. They rest on a frictionless, horizontal surface. A second string, attached only to the 6.0-kg block, has horizontal force = 45 N applied to it. Both blocks accelerate. Find the tension in the string between the blocks.



T= 27 N


Assuming that the string joining both masses is massless  and inextensible, both masses accelerate at the same rate.

So, we can treat to both masses as a single system, and apply Newton's 2nd Law to both masses.

In this way, we can get the value of the acceleration without taking into account the tension in the string, as it is an internal force (actually a action-reaction pair).

Newton's 2nd law is a vector equation, so we can decompose the forces along perpendicular axis in order to convert it in two algebraic equations.

We can choose one axis as parallel to the horizontal surface (we call it x-axis, being the positive direction the one of  the movement of the blocks due to the horizontal force applied to the 6.0 kg block), and the other, perpendicular to it, so it is vertical (we call y-axis, being the upward direction the positive one).

Taking into account the forces acting  on both masses, we can write both equations as follows:

Fy = N- (m₁+m₂)*g = 0 (as there is no movement in the vertical direction)

Fx = Fh = (m₁ + m₂) * a ⇒ 45 N = 15.0 kg * a

⇒ a = 45 N / 15.0 kg = 3 m/s²

Now, in order to get the value of the tension T, we can choose as our system, to any mass, and apply Newton's 2nd Law again.

If we choose to the mass of 6.0 kg, in the horizontal direction, there are two forces acting on it, in opposite directions: the  horizontal applied force of 45 N, and the tension in the string that join both masses.

The difference of both forces, must be equal to the mass (of this block only) times the acceleration, as follows:

F- T = m₂* a ⇒ 45 N - T = 6.0 kg * 3 m/s²

⇒ T = 45 N -18 N = 27 N

We could have arrived to the same result taking the 9.0 Kg as our system, as the only force acting in the horizontal direction is just the tension in the string that we are trying to find out, as follows:

F = m₁*a = 9.0 kg* 3 m/s² = 27 N


A ball with a mass of 1.5 kilograms is tied to the end of a rope. The ball is pulled to a height of 0.5 meters above the ground and released. The ball has joules of potential energy at position B. At position A, all of the energy changes to kinetic energy. The velocity of the ball at position A is meters/second. Assume there’s no air resistance. Use g = 9.8 m/s2 , PE = m × g × h, and


Solve the potential energy at point B

PE = mgh

Where m is the mass

G is the acceleration due to gravity 9.8 m/s2

H is the height

PE = ( 1.5 kg) ( 9.8 m/s2) (0.5 m)

PE = 7.35 J


Solve the velocity using the

KE = 0.5mv^2

Where ke is the kinetic energy

M is the mass

V is the velocity

Since all energy is converted to KE

So KE = PE


7.35 = 0.53(1.5) v^2

V = 3.13 m/s

The velocity of the ball at position A is equal to 3.13 m/s.

Given the following data:

  • Mass of ball = 1.5 kilograms.
  • Height = 0.5 meters.
  • Acceleration due to gravity = 9.8

How to calculate potential energy.

Mathematically, potential energy is given by this formula:


  • m is the mass.
  • h is the height.
  • g is acceleration due to gravity.

Substituting the given parameters into the formula, we have;

P.E = 7.35 Joules.

Assuming there’s no air resistance, the potential energy would be equal to kinetic energy.

V = 3.13 m/s.

Read more on potential energy here:


Transform boundaries are classified under which type of fault?



Strike-slip fault


Transform boundaries play the role of connecting the other plate boundary segments.

When the plates are rubbed against each other, they result in enormous amount of stresses which leads to the breaking of the part of a rock causing earthquakes. Places of occurrence of these breaks are termed as faults.

Strike slip faults results from compression which takes place horizontally, but but in this the rock displacement  releases energy and takes place in a horizontal direction which is parallel to the force of compression.


What is the primary energy transformation that occurs when a match is lit? A. Electrical energy is transformed into heat and light. B. Chemical energy is transformed into heat and light. C. Chemical energy is transformed into electrical energy. D. Heat and light are transformed into chemical energy.


B. chemical energy is transformed into heat and light

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