Year 8 Science – Forces 1
Practise applying ideas about electrostatic and gravitational forces, orbits, weight calculations, electromagnets and simple machines to new examples. 20 questions. 25 minutes.
A student pulls the same block at a steady speed across three surfaces and reads a spring balance each time. What is the independent variable?
| Surface | Spring balance reading (N) |
|---|---|
| Tiles | 3 |
| Wood | 5 |
| Carpet | 8 |
A balloon is rubbed on wool and held above small scraps of tissue paper. The scraps jump up to the balloon. Which force lifts the scraps?
Choose the word that completes each blank.
Two objects with like charges 1 each other, and two objects with opposite charges 2 each other.
Blank 1: attract · repel · ignore
Blank 2: repel · ignore · attract
A bag of rice has a mass of 4 kg. Using g = 10 N/kg, what is its weight on Earth?
Circle 2 words in the sentence below.
Click the two quantities that are measured in newtons.
weightfrictionmassspeed
A rover has a mass of 50 kg. On the Moon, g = 1.6 N/kg. What is the rover's weight on the Moon?
Choose the word that completes each blank.
When an astronaut walks on the Moon, her mass is 1 and her weight is 2 compared with Earth.
Blank 1: unchanged · smaller · larger
Blank 2: larger · smaller · unchanged
Which statement best explains why the Moon stays in orbit around Earth?
Circle 2 words in the sentence below.
Click the two things that increase friction between a runner's shoe and the ground.
treadoilicerough surface
Choose the word that completes each blank.
A single fixed pulley changes only the 1 of the force. A ramp needs less force, but the load moves a greater 2.
Blank 1: direction · size · energy
Blank 2: mass · weight · distance
A student pushes a box 3 m across the floor with a steady 20 N force. How much energy is transferred to the box?
An Aboriginal hunter uses a woomera (spear-thrower) to throw a spear. How does the woomera help?
Choose the word that completes the blank.
Spinning a fire drill against wood uses friction to change kinetic energy mostly into 1 energy.
Blank 1: thermal · electrical · magnetic
A crate weighs 200 N on Earth. Using g = 10 N/kg, what is the mass of the crate?
Choose the word that completes each blank.
The gravitational pull between two objects is stronger when their masses are 1 and the distance between them is 2.
Blank 1: smaller · larger · equal
Blank 2: greater · fixed · smaller
A satellite moves from a low orbit to an orbit much further from Earth. What happens to Earth's gravitational pull on it?
Circle 2 words in the sentence below.
Click the two changes that make an electromagnet stronger.
more cellswooden coremore turnsfewer cells
A student pulls a trolley up ramps of different lengths to the same height. What does the table show?
| Ramp length (m) | Force needed (N) |
|---|---|
| 1 | 80 |
| 2 | 40 |
| 4 | 20 |
Choose the word that completes each blank.
An electromagnet lifts a greater number of paperclips when it has 1 turns of wire and 2 current.
Blank 1: fewer · the same · more
Blank 2: less · more · the same
A student tests an electromagnet with one battery and an iron nail. Based on the pattern, how many paperclips would 20 turns pick up?
| Number of turns | Paperclips lifted |
|---|---|
| 5 | 2 |
| 10 | 4 |
| 15 | 6 |