SQA Higher Physics Area 1 Our Dynamic Universe: a complete overview of motion, forces, momentum, gravitation, relativity and the expanding universe

What Area 1 actually demands

Our Dynamic Universe is the largest area of SQA Higher Physics, running from everyday motion to the scale of the cosmos. It applies a small set of relationships to a wide range of contexts: describing motion with the equations of motion and graphs, analysing forces with Newton's laws, tracking momentum and impulse through collisions, treating projectiles and gravity, and finally reaching the strange behaviour of objects near the speed of light and the expansion of the universe. The examiners test confident calculation, correct sign conventions, and clear physical explanation.

This guide walks through all six key areas of the area, then sets out the patterns the SQA repeats. Each key area has a matching dot-point page with practice questions; this overview ties them together.

Equations of motion

The area opens with the equations of motion: the difference between scalars (magnitude only) and vectors (magnitude and direction), the four equations for constant acceleration, and motion graphs. On a velocity-time graph the gradient is the acceleration and the area under the line is the displacement. The recurring habit is choosing a positive direction so that opposite quantities carry a negative sign.

Forces, energy and power

Forces, energy and power applies Newton's laws, free-body diagrams and the resolution of forces (including on a slope), then the work-energy relationships for kinetic energy, gravitational potential energy and power. An unbalanced force produces acceleration given by $F = ma$, and work done transfers energy.

Collisions, momentum and impulse

Collisions, momentum and impulse uses the conservation of momentum, $p = mv$, in one dimension for collisions and explosions, distinguishes elastic from inelastic collisions by comparing kinetic energy, and links impulse to force and time through $Ft = mv - mu$, the area under a force-time graph.

Gravitation

Gravitation resolves projectile motion into independent horizontal and vertical motions linked by a common time, then applies Newton's law of universal gravitation, $F = \frac{Gm_1m_2}{r^2}$, an inverse-square attractive force, and the idea of a gravitational field around every mass.

Special relativity

Special relativity rests on two postulates, including the constancy of the speed of light, and leads to time dilation ($t' = \frac{t}{\sqrt{1 - (v/c)^2}}$, a moving clock runs slow) and length contraction ($l' = l\sqrt{1 - (v/c)^2}$, a moving object is shorter along its motion). These effects only matter near the speed of light.

The expanding universe

The expanding universe uses the Doppler effect to explain frequency shifts, the redshift of galaxies showing they recede, Hubble's law $v = H_0 d$ giving an age of the universe, and the evidence for the Big Bang: galactic redshift and the cosmic microwave background.

How Area 1 is examined

A typical SQA profile for Our Dynamic Universe:

• Calculations. Equations of motion, $F = ma$, work, energy and power, momentum and impulse, projectile motion, gravitational force, time dilation and length contraction, and Hubble's law.
• Graph work. Reading gradients and areas from velocity-time and force-time graphs.
• Explanation. Newton's laws, the conditions for the equations of motion, the postulates of relativity, and the evidence for the Big Bang.

Check your knowledge

A mix of recall and calculation questions covering Area 1. Attempt them, then check against the solutions.

1. State the difference between a scalar and a vector. (1 mark)
2. A car accelerates from rest at $2\text{ m s}^{-2}$ for $5\text{ s}$. Find its final velocity. (2 marks)
3. State the law of conservation of momentum. (1 mark)
4. State what happens to a moving clock as measured by a stationary observer. (1 mark)
5. State what the redshift of a galaxy tells you about its motion. (1 mark)
6. Write Newton's law of universal gravitation. (1 mark)