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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 3 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 74 m east and then 14 m west along a straight line. Find the total distance travelled. Round to 3 decimal places if needed. Answer in m.
m
2Motion & graphsTwo carts approach each other on a straight track at 24 m/s and 22 m/s. How fast is their separation decreasing? Round to 3 decimal places if needed. Answer in m/s.
m/s
3Forces & equilibriumA 4 kg cart has horizontal forces 34 N right and 74 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 & equilibriumA mass of 53 kg is in a model gravitational field of 9.8 N/kg. Find its weight. Round to 3 decimal places if needed. Answer in N.
N
5Energy, work & powerA device receives 830 J and has useful-energy efficiency 40%. Find the useful output energy. Round to 3 decimal places if needed. Answer in J.
J
6Energy, work & powerA model device transfers energy at constant power 960 W for 65 s. Find the transferred energy. Round to 3 decimal places if needed. Answer in J.
J
7Pressure & fluidsA normal force of 661 N acts uniformly over 0.41 m². Find the pressure. Round to 3 decimal places if needed. Answer in Pa.
Pa
8Pressure & fluidsAn object displaces 0.003 m³ of liquid of density 1000 kg/m³ with g = 10 N/kg. Find buoyant force.
N
9Waves & soundCan ordinary sound propagate through a perfect vacuum?
10Waves & soundAn echo returns after 330 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
11Electricity & circuitsA constant current of 2.1 A flows for 64 s. Find transferred charge. Round to 3 decimal places if needed. Answer in C.
C
12Electricity & circuitsA model device uses constant power 1700 W for 7 h. Find the energy in kilowatt-hours. Round to 3 decimal places if needed. Answer in kWh.
kWh