DE 4

What is the term for an object's overall, or final, change in position?

• Travel

• Displacement

• Transfer

• Distance

Answer explanation

We say "final" here because while an object is moving, we might refer to its velocity or acceleration, both having to do with rates of change in position, but when it stops moving, we talk about its displacement—its ultimate change in position.

How many colours can be found in sunlight?

• five

• seven

• nine

• eleven

Physics is often split into two classifications -classical physics and quantum physics. The world of quantum and nuclear physics is continuously evolving and has managed to capture the attention of the public, such as the experiments carried out by CERN. In the early days, the field had input from the likes of Planck and Einstein, the latter of which came up with the equation E = phi + Ek(max). What effect does this equation attempt to explain?

• Bohr Effect

• Interference Effect

• Resonance Effect

• Photoelectric Effect

Answer explanation

The equation E = phi + Ek(max) describes the behaviour of photon-electron interaction. E stands for the energy of an incident photon and the energy of a photon is dependent upon its frequency (E = Planck's constant x frequency) such that a greater photon frequency results in a greater photon energy.

what's the difference between "pressure" and "force"?

• "Pressure" is always atmospheric.

• "Pressure" is the ratio of force to area where it's applied.

• "Force" always results in motion, "pressure" not necessarily.

• "Pressure" is always related to heat.

Answer explanation

The word itself simply refers to the way force spreads out over the surface area to which it's applied.

Pressure is a concept that is used extensively when considering the physics of gases and liquids. Which of the following is a simple explanation of what pressure is?

• Power per unit time

• Mass per unit acceleration

• Force per unit area

• Mass per unit volume

Answer explanation

To expand on the concept slightly, the force applied is required to be perpendicular to the surface of the area. If the force is applied at an angle, trigonometry and the vertical component of the applied force can be used to obtain the value of the perpendicular force.

Physics is known for its equations and calculations for the forces acting on an object that travels in a straight line. However, there is also a force that causes objects to move in a circular motion, such as the movement of a simple pendulum that rotates 360 degrees about an axis. What is this force that is also the subject of the equation F = (mv^2)/r?

• Electromagnetic force

• Inertial force

• Centripetal force

• Quantum force

What does a "K" usually stand for in physics equations?

• Constant

• Kilograms

• Kinesis

• Kilometers

What is the opposite of kinetic energy?

Static energy

• Static energy

• Positional energy

• Potential energy

• Scalar energy

Answer explanation

An object at rest, because of its mass and position, has a certain amount of potential energy. Think of a cannonball suspended at a height by a fraying cable. If that cable breaks, the ball has a lot of ability to exert force and do damage.

Sound travels fastest through which of the following?

• Liquids

• Solids

• Air

• Vacuum

Answer explanation

Does sound travel fastest in a vacuum or steel?

The speed of sound, therefore, is fastest in solids, followed by liquids (less dense than solids) and then gas (least dense). Since steel is a solid substance, so sound travels fastest in it. Sound cannot travel in a vacuum as there is no material medium.

Speed has...

• both direction and magnitude.

• only magnitude and no direction.

• only direction and not magnitude

• neither direction nor magnitude.