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Grade 8 · Physics

Grade 8 Physics diagnostic

12 questions on motion & graphs, forces & equilibrium, energy, work & power, pressure & fluids, waves & sound and electricity & circuits. Answer what you can, then check your answers to see which topics are secure and what to practise next.

12 questions6 topicsAbout 15 minutesSet 5 of 5

Skip a question if you do not know the answer. It is better than guessing, because it shows what to practise.

1Motion & graphsA robot moves 90 m east and then 3 m west along a straight line. Find the total distance travelled. Round to 3 decimal places if needed. Answer in m.
m
2Motion & graphsOn an east-positive axis, position changes from 4 m to -23 m in 23 s. Find the signed average velocity. Round to 3 decimal places if needed. Answer in m/s.
m/s
3Forces & equilibriumA 11 kg cart has horizontal forces 77 N right and 118 N left. No other horizontal forces act. Taking right as positive, find its acceleration. Round to 3 decimal places if needed. Answer in m/s².
m/s²
4Forces & equilibriumOn a weightless balanced beam, 24 N acts 10 m left of the pivot. What downward force at 4 m right balances it? Forces are perpendicular to the beam. Round to 3 decimal places if needed. Answer in N.
N
5Energy, work & powerA model device transfers energy at constant power 460 W for 58 s. Find the transferred energy. Round to 3 decimal places if needed. Answer in J.
J
6Energy, work & powerA device receives 140 J and has useful-energy efficiency 65%. Find the useful output energy. Round to 3 decimal places if needed. Answer in J.
J
7Pressure & fluidsA normal force of 388 N acts uniformly over 0.77 m². Find the pressure. Round to 3 decimal places if needed. Answer in Pa.
Pa
8Pressure & fluidsA floating object weighs 20 N in a liquid with g = 10 N/kg. Find the mass of displaced liquid.
kg
9Waves & soundAn echo returns after 770 ms. The sound speed in this medium is 1500 m/s. Find the distance to the stationary reflector. Round to 3 decimal places if needed. Answer in m.
m
10Waves & soundA wave has frequency 83 Hz and wavelength 2.2 m. Find its speed. Round to 3 decimal places if needed. Answer in m/s.
m/s
11Electricity & circuitsA model device uses constant power 25 W for 7 h. Find the energy in kilowatt-hours. Round to 3 decimal places if needed. Answer in kWh.
kWh
12Electricity & circuitsAn ohmic resistor of 57 Ω has potential difference 29 V. Find current. This is a paper calculation, not a construction instruction. Round to 3 decimal places if needed. Answer in A.
A