This page holds ten original mixed questions across the Physics course, each with a worked answer. Use them as a diagnostic: the aim is to find which skill fails, not just to count marks.
Take g = 10 N/kg where gravity is needed. The original mixed-practice builder can assemble longer printable sessions once you know which skills to target.
How to use this set
- Attempt a question on paper before opening the answer.
- Write units on every line of working.
- Mark yourself honestly and log each error in the mistake log and retest queue.
- Use the routing table at the end to choose what to study next.
The questions
1. Speed. A cyclist covers 240 m in 30 s. Calculate her average speed.
Show answer
speed = distance ÷ time = 240 ÷ 30 = 8 m/s. Check: 8 × 30 = 240.
2. Units. Convert 72 km/h into m/s.
Show answer
72 km = 72 000 m and 1 h = 3600 s. 72 000 ÷ 3600 = 20 m/s. Check: 20 × 3.6 = 72.
3. Density. A metal block has mass 540 g and volume 200 cm³. Give its density in g/cm³ and in kg/m³.
Show answer
density = 540 ÷ 200 = 2.7 g/cm³. Since 1 g/cm³ = 1000 kg/m³, the density is 2700 kg/m³.
4. Pressure. A force of 600 N acts on an area of 0.030 m². Calculate the pressure.
Show answer
pressure = force ÷ area = 600 ÷ 0.030 = 20 000 Pa (20 kPa). Check: 20 000 × 0.030 = 600.
5. Moments. A 40 N force acts 0.25 m from a pivot. (a) Find its moment. (b) What force at 0.50 m from the pivot on the other side balances it?
Show answer
(a) moment = 40 × 0.25 = 10 N m.
(b) For balance the moments are equal, so F × 0.50 = 10, giving F = 10 ÷ 0.50 = 20 N. Double the distance needs half the force, so 20 N at 0.50 m against 40 N at 0.25 m is consistent.
6. Graph. A vehicle accelerates uniformly from rest to 12 m/s in 4.0 s. Find (a) the acceleration and (b) the distance travelled in that time.
Show answer
(a) a = change in speed ÷ time = 12 ÷ 4.0 = 3.0 m/s².
(b) distance is the area under the speed-time graph, a triangle: ½ × 4.0 × 12 = 24 m. Check with average speed: 6 m/s × 4.0 s = 24 m.
7. Heat. How much energy is needed to heat 0.50 kg of water from 20 °C to 60 °C? The specific heat capacity of water is 4200 J/(kg °C).
Show answer
Temperature change = 60 − 20 = 40 °C. Q = mcΔθ = 0.50 × 4200 × 40 = 84 000 J. Check: 0.50 × 4200 = 2100, and 2100 × 40 = 84 000.
8. Waves. A sound wave has frequency 850 Hz and wavelength 0.40 m. Calculate its speed.
Show answer
v = f × λ = 850 × 0.40 = 340 m/s. Check: 340 ÷ 0.40 = 850.
9. Electricity. A 12 V supply is connected across a 4.0 Ω resistor. Find (a) the current and (b) the energy transferred in 2.0 minutes.
Show answer
(a) I = V ÷ R = 12 ÷ 4.0 = 3.0 A.
(b) power = V × I = 12 × 3.0 = 36 W. Time = 2.0 × 60 = 120 s. Energy = 36 × 120 = 4320 J. Check: 36 × 100 = 3600, plus 36 × 20 = 720, total 4320.
10. Half-life. A sample contains 80 g of a radioactive isotope with half-life 6.0 hours. How much remains after 18 hours?
Show answer
18 ÷ 6.0 = 3 half-lives. 80 → 40 → 20 → 10 g. Check: 80 ÷ 2³ = 80 ÷ 8 = 10.
If you got these wrong
| Error you made | Likely cause | Go to |
|---|---|---|
| Q1, Q2 wrong number | Units or conversion slip | Measurement and quantities |
| Q3 wrong unit | Density conversion | Mass, weight and density |
| Q4, Q5 wrong | Force, area or distance confusion | Pressure and moments |
| Q6 wrong | Gradient and area mixed up | Motion and graphs |
| Q7 wrong | Temperature change or unit | Heat calculations |
| Q8 wrong | Wave equation selection | Wave behaviour |
| Q9 wrong | Power and time units | Circuits and electrical energy |
| Q10 wrong | Counting half-lives | Half-life and background |
Words that sound alike are a separate source of errors, so keep the Physics terminology guide open while marking.
Where to go next
Each module also has its own mixed practice set with explained answers, linked from its page in the Physics learning guide. For a plan that uses this page weekly, see the revision method.
If marking shows a pattern you cannot break alone, online one-to-one Physics tuition lets a teacher work on it with you.