PHY Unit 2

Length (DISTANCE)

Total extent of a path followed between two points

meters with no direction

Symbol- I

SI units- m (meters

Area

SI units- m² (meters squared)

Symbol- A

Area of a shape

Rectangle- LxW

Square- side length squared

Circle pir²

Surface of sphere- 4/3 pir³

Volume

Symbol- V

SI unit- m³ (meters cubed)

Volume of a solid:

Rectangular solid: LxWxH

Cube: side length cubed

Sphere: 4/3pir³

mass

Amount of matter

Symbol- m

SI units- Kg

time

Elapsed time

Symbol- t

SI units s (seconds)

Displacement

change in position (shortest path from start point to end point (vector)

Meters with a direction

Symbol- d

SI unit- m

Speed

Rate of change of distance (length) / time (scalar)

m/s with no direction

Symbol- c

SI unit- m/s

Velocity

Rate of Change of displacement/time (vector)

m/s with a direction

Symbol- v

SI unit- m/s

Acceleration

Rate of Change in velocity/time (vector)

m/s²

Symbol- a

SI unit- m/s²

Force

A push or pull; accelerates a mass/mass x acceleration; F=ma (vector)

Newtons

Symbol- F

SI unit- N /newtons (Kg m/s²)

Pressure

force per unit area (scalar)

Pascals

Symbol- p

SI unit- Pa (pascals)

Work

Force times distance (scalar)

Joules

Symbol- W

SI unit- J / joules

Power

work per unit time

Watts

Work/time (scalar)

Symbol- P

SI unit- w (watts)

Intensity

power per unit area

watts/m²

Power/area (vector)

Symbol- I

SI unit- w/m² (watts per square meter)

Period

Time required for one complete cycle of vibration. (To compute divide total time by number of cycles completed in that time)

T= 1/f

Symbol- T

SI unit- seconds

Period

Time required for one complete cycle of vibration. (To compute divide total time by number of cycles completed in that time)

T= 1/f

Symbol- T

SI unit- seconds

When an object is at equilibrium

the forces acting on it cancel (add up to zero) and it will only move if forces change

Increasing the rate at which work is done (expanding the same amount of energy in a shorter time) will

Increase the power

Newton’s third law of motion states that

Every force produces a counterforce that is equal in magnitude and opposite in direction

• for every action (force) there is an equal and opposite reaction (force)

When it passes through equilibrium point of its motion, a swinging pendulum has

Greatest kinetic energy and lowest potential energy

When it passes through equilibrium point of its motion, a swinging pendulum has

Greatest kinetic energy and lowest potential energy

At the turning points of a pendulum that is executing simple harmonic motion, the system has?

Maximum potential energy (potential energy is maximum and kinetic energy is zero)

At the turning points of a pendulum that is executing simple harmonic motion, the system has?

Maximum potential energy (potential energy is maximum and kinetic energy is zero)

As you demonstrated in the lab, if you increase the length of the string of a pendulum, the frequency of vibration will ____ and if you decrease the length the frequency of vibration will _____

Decrease, increase

Velocity is a ______ quantity in that it has _____

Vector, magnitude and direction

Displacement is a _____ quantity in that it has _____

Vector, magnitude and direction

A mouse runs in a complete circle, coming back to the starting point. Which of the following is/are true?

The magnitude of the displacement is zero and the average velocity is zero m/s

Increasing the area over which power is expanded will _____

Decreases the intensity

Newton’s first law of motion the law of inertia states that apply

An object that is at rest will stay at rest unless a force acts on it

An object that is in motion will stay in motion will stay in motion unless force acts on it

What’s false about friction?

It depends on the velocity of the objects

All physical quantities can be expressed in terms of the three fundamental physical quantities which are?

Mass, length and time

The density of a material is the

Mass divided by the volume

If an object experiences a force of 4 N due north and a force of 4 N due south, it will experience a net force of magnitude _____N and it ____

0, will not move

(4 N north - 4 N south = 0 net force)

What happens when a pendulum is pulled away from its equilibrium position and briefly held there, and then released?

It gains kinetic energy as it moves towards equilibrium and swings past it

A pendulum oscillates in simple harmonic motion for small angles

Decreasing the area over which a force is applied will _____

Increase the pressure (pressure = force/area)

Increasing force that is used to move an object over a fixed distance will _____

Increase the work

(Work= force x distance) (power=work/time)

As you demonstrated in the lab, if you increase the mass in a mass spring system, the frequency of vibration will

Decrease

Newton’s second law of motion states that acceleration of a body is

Directly proportional to the applied force and inversely proportional to its mass

A mouse runs out of a mouse hole into a room, turns around and runs back to its starting point, what is true?

Displacement is zero

Average velocity is zero

Friction (characteristics such as objects to drag due to motion in fluids such as air, what happens to the energy that is dissipated via friction, is it conserved?)

energy is conserved but some of it is dissipated as heat and is no longer available for movement of a system

Speed is a ___ quantity in that it has ____

scalar; magnitude

Potential Energy

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Kinetic energy

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Scalar quantity (which physical quantities are scalar)

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Vector quantity (which physical quantities are vectors)

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Conservation of energy

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Characteristics of simple harmonic motion and the interchange between kinetic and potential energy during the cycle of vibration

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