GED Science : GED Science

Study concepts, example questions & explanations for GED Science

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Example Questions

Example Question #1 : Ged Science

Which of the following best illustrates Newton's Second Law?

Possible Answers:

When two cymbals collide, some kinetic energy is converted into sound

A ball is rolled across a table and does not stop until it hits an area with friction

If an object is not accelerating, then the net force on it is zero

As a hammer hits a nail, the nail also exerts a force on the hammer

Correct answer:

If an object is not accelerating, then the net force on it is zero

Explanation:

Newton's Second Law is best represented as an equation, in which the product of mass and acceleration is equal to net force:

\(\displaystyle F_{net}=ma\)

By this principle, if there is zero acceleration, then the force must also be zero.

\(\displaystyle F_{net}=m(0\frac{m}{s^2})=0N\)

A non-zero acceleration must be present if there is a non-zero net force.

Example Question #2 : Ged Science

Which of the following is the best example of Newton's Third Law?

Possible Answers:

A spinning top will not fall unless there is friction with the surface on which it spins

The force of being hit by an object is determined by its mass and acceleration

When two objects collide, the total initial and total final momentum will be equal

If an object's weight rests on the floor, then the floor will exert a normal force on the object

Correct answer:

If an object's weight rests on the floor, then the floor will exert a normal force on the object

Explanation:

Newton's Third Law states that for every action there is an equal and opposite reaction. In other words, a force will act in equal and opposite directions on the two objects involved.

Weight and normal force are a specific example of this principle. Acceleration due to gravity creates a downward force, known as weight. This force, however, results in zero downward acceleration when the object is resting on a surface (a book does not fall through a table, for example). For the forces to be in equilibrium, there must be a counteracting upward force. This is known as the normal force, which is equal and opposite to the weight of the object. While weight pulls the object down, normal force pushes it up to create equilibrium.

Example Question #1 : Displacement

A car drives \(\displaystyle \small 5\) miles east and \(\displaystyle \small 12\) miles north. What is the total displacement of the car?

Possible Answers:

\(\displaystyle 17\ \text{miles}\)

\(\displaystyle 7\ \text{miles}\)

\(\displaystyle 13\ \text{miles}\)

\(\displaystyle 60\ \text{miles}\)

Correct answer:

\(\displaystyle 13\ \text{miles}\)

Explanation:

The car has covered a total distance of \(\displaystyle \small 17\) miles, however, displacement and distance are not the same thing. Distance is simply the measure of how far the car have moved, regardless of direction. Displacement is a vector quantity, and takes direction into account. Displacement measures the total distance only between the car's starting point and ending point.

To solve this question, it is best to draw a sketch. The resulting sketch will be a right triangle with the hypotenuse equal to the displacement. The Pythagorean Theorem can be used to solve the problem.

Question_1

\(\displaystyle \small a^2+b^2=c^2\)

\(\displaystyle \small 5^2+12^2=d^2\)

\(\displaystyle \small 25+144=d^2\)

\(\displaystyle \small 169=d^2\)

\(\displaystyle \small \sqrt{169}=\sqrt{d^2}\)

\(\displaystyle \small 13=d\)

Example Question #3 : Ged Science

A car travels due east for two hours and covers 144km. What is the car's average velocity in meters per second?

Possible Answers:

\(\displaystyle \small 0.05\frac{m}{s}\)

\(\displaystyle \small 72000\frac{m}{s}\)

\(\displaystyle \small 72\frac{m}{s}\)

\(\displaystyle \small \small 20\frac{m}{s}\)

Correct answer:

\(\displaystyle \small \small 20\frac{m}{s}\)

Explanation:

This question requires us to convert between units, then solve for the velocity.

First, convert kilometers to meters. There are 1000m in 1km.

\(\displaystyle 144km\times \frac{1000m}{1km}=144000m\)

Then, convert hours to seconds. There are 60min in 1hr, and 60sec in 1min. In other words, there are 3600s in 1hr.

\(\displaystyle 2hr\times \frac{60min}{1hr}\times \frac{60s}{1hr}=7200s\)

Now that you have both the distance in meters and the time in seconds, you can find the velocity. Velocity is equal to the distance divided by the time.

\(\displaystyle v=\frac{d}{t}\)

\(\displaystyle v=\frac{144000m}{7200s}=20\frac{m}{s}\)

Example Question #3 : Ged Science

A ball that has a mass of 2kg is launched upward at a velocity of \(\displaystyle \small 4\frac{m}{s}\). What is the initial kinetic energy of the ball?

Assume the ball is traveling in a vacuum.

Possible Answers:

\(\displaystyle \small 32J\)

\(\displaystyle \small 16\frac{kg \cdot m}{s}\)

\(\displaystyle \small 16J\)

\(\displaystyle \small 8\frac{kg\cdot m}{s}\)

Correct answer:

\(\displaystyle \small 16J\)

Explanation:

Kinetic energy (measured in Joules) can be solved using the equation:

\(\displaystyle KE=\frac{1}{2}mv^2\)

We are given both the mass of the projectile (2kg) and its velocity (\(\displaystyle \small 4\frac{m}{s}\)). Using these values, we can solve the equation.
\(\displaystyle KE=\frac{1}{2}(2kg)(4\frac{m}{s})^2\)

\(\displaystyle KE=\frac{1}{2}(2kg)(16\frac{m^2}{s^2})\)

\(\displaystyle KE=16\frac{kg\cdot m^2}{s^2}=16J\)

Example Question #2 : Ged Science

Which of the following measures depicts the amplitude?

Question_2

Possible Answers:

C

B

A

D

Correct answer:

A

Explanation:

The amplitude measures the greatest displacement (either positive or negative) of a wave from the x-axis. Visually, the amplitude appears to be the distance from the x-axis (center line) to the top of one peak. In the figure, this value is given by A.

The other relevant measure given in the figure is segment D, which measures the distance between two peaks. This distance is known as the wavelength.

Segments B and C do not provide useful measurements of the wave function.

Example Question #1 : Chemistry

Molecules are constantly moving. In which state of matter do molecules move the fastest?

Possible Answers:

Gases

Molecules move at the same rate in both gases and liquids

Liquids

Molecules move at the same rate in all three states of matter

Solids

Correct answer:

Gases

Explanation:

The movement of particles is important in differentiating the states of matter. Solids have the lowest molecular energy; their molecules barely vibrate and are generally trapped in lattice structures. Molecules in liquids are able to move more freely, resulting in the fluidity of the liquid state. Gas molecules have even more freedom of movement, allowing the gas to expand to fill a space.

Consider that energy (such as heat) must be added to convert a solid to a liquid or a liquid to a gas. That energy goes to make the molecules move faster and increase the temperature of the compound. Gases require the most energy (consider boiling water), and will have the fastest moving molecules.

Example Question #1 : Matter And Moles

Atomic mass values:

\(\displaystyle H\rightarrow 1.0\frac{g}{mol}\)

\(\displaystyle S\rightarrow 32.1\frac{g}{mol}\)

\(\displaystyle O\rightarrow 16.0\frac{g}{mol}\)

Convert the following mass to moles:

\(\displaystyle 12.05g\ H_2SO_4\)

Possible Answers:

\(\displaystyle 1181.80\ \text{moles}\)

\(\displaystyle 7.12\times 10^{26}\ \text{moles}\)

\(\displaystyle 0.12\ \text{moles}\)

\(\displaystyle 7.40\times 10^{24}\ \text{moles}\)

Correct answer:

\(\displaystyle 0.12\ \text{moles}\)

Explanation:

To convert grams to moles, use the molecular weight of the molecule. This is found by adding the mass of each atom.

\(\displaystyle H_2SO_4\rightarrow 2(H)+1(S)+4(O)\)

\(\displaystyle 2(1.0\frac{g}{mol})+(32.1\frac{g}{mol})+4(16.0\frac{g}{mol})=98.1\frac{g}{mol}\)

\(\displaystyle \frac{98.1g\ H_2SO_4}{1mol\ H_2SO_4}\)

Now we can use the molecular mass to convert the given mass in the question to moles. Make sure to align the values so that the units cancel out.

\(\displaystyle 12.05g\ H_2SO_4\times \frac{1mol\ H_2SO_4}{98.1g\ H_2SO_4}=0.12mol\ H_2SO_4\)

Example Question #2 : Matter And Moles

How many molecules are in 3.72mol of fluorine?

Possible Answers:

\(\displaystyle 70.68\ \text{molecules}\)

\(\displaystyle 0.20\ \text{molecules}\)

\(\displaystyle 2.24\times10^{24}\ \text{molecules}\)

\(\displaystyle 6.18\times10^{-24}\ \text{molecules}\)

Correct answer:

\(\displaystyle 2.24\times10^{24}\ \text{molecules}\)

Explanation:

Convert from moles to molecules using Avogadro's number:

\(\displaystyle (\text{moles})\times(\frac{6.02\times10^{23}\text{molecules}}{\text{mole}})=\text{molecules}\)

Use the moles given in the question to solve.

\(\displaystyle 3.72mol\times \frac{6.02\times10^{23}\ \text{molecules}}{1mol}=2.24\times10^{24}\ \text{molecules}\)

Example Question #2 : Chemistry

Which of the following types of chemical bonds is very strong and involves transfer of an electron between atoms?

Possible Answers:

Ionic bonds

Hydrogen bonds

Disulfide bonds

Covalent bonds

Correct answer:

Ionic bonds

Explanation:

There are two primary bond types: ionic bonds and covalent bonds. Ionic bonds involve the transfer of an electron between atoms, while covalent bonds require atoms to share an electron between them. Ionic bonds are the stronger of the two. Ionic bonds usually form between a metal and a non-metal (for example, NaCl), while covalent bonds usually form between two non-metals (for example, HCl).

Hydrogen bonds are a type of intermolecular force and are similar to a very weak covalent bond. Hydrogen bonds are not actual bonds, and do not chemically link atoms together; they are strictly physical interactions. Disulfide bonds are covalent bonds between sulfur atoms that help form protein structure.

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