Motion, Forces and Energy

Study if ur cool.

What is speed and how to calculate it.

Speed is distance travelled per unit time, v = s/t

What is acceleration and how to calculate it.

Acceleration of an object moving in a straight line is the rate of change of its velocity over time, calculated as a = (vf - vi)/t, where vf is final velocity and vi is initial velocity.

What is mass?

Measure of the quantity of matter in an object

What is weight?

The gravitational force on an object that has mass.

Define gravitational field strength.

Gravitational force per unit mass. W/M

What is gravitational field strength equivalent to?

Acceleration of free fall.

Define density.

Mass per unit volume. p = m/V.

How to calculate force?

F = ma

Types of potential energy.

kinetic, gravitational potential, chemical, elastic (strain), nuclear, electrostatic and internal (thermal)

How to calculate kinetic energy?

E_k = 1/2 x m x v²

How to calculate gravitational potential energy?

E_p = mgh

What is work equal to?

W = F x d = ΔE

What energy resources don’t require the sun?

Geothermal, nuclear and tidal.

What’s the difference between nuclear fusion and nuclear fission.

Nuclear fusion is in the sun. Nuclear fission is in nuclear reactors.

Define power

Work done per unit time, or energy transferred per unit time.

Define pressure and how to calculate.

Force per unit area, p = F/A

Define features of a transverse wave.

The direction of vibration is at a right angle to the direction of propagation. Examples are electromagnetic radiation, water waves, seismic S-waves.

Define feature of a longitudinal wave

The direction of vibration is parallel to the direction of propagation and understand that sound waves and seismic P waves are longitudinal.

What is the equation for wave speed?

v = f λ

What are the characteristics of an image in a mirror?

Same size, same distance, laterally inverted.

What’s the order of the visible spectrum?

red, orange, yellow, green, blue, indigo, violet

What is the order of the electromagnetic spectrum?

radio, microwave, infrared, visible, ultraviolet, X-ray, gamma

What is the speed of electromagnetic waves in a vacuum?

3.0 × 10⁸

What are the harmful effects of ultraviolet light?

damage to surface cells and eyes, leading to skin cancer and eye conditions

What are the harmful effects of gamma and x-rays?

mutation or damage to cells in the body

How does a change in amplitude affect the sound?

• Greater amplitude = louder sound

• Smaller amplitude = quieter sound

How does a change in frequency affect the sound?

• Higher frequency = higher pitch (e.g. a whistle or bird chirp)

• Lower frequency = lower pitch (e.g. a drum or deep voice)

What is ultrasound?

A frequency higher than 20 kHz

What is the hearing range of humans?

20 Hz to 20 kHz

What affects speed of sound?

The more dense and solid the medium is the faster sound travels/

What is sound?

A series of compressions and rarefactions.