# Speed and forces

> Grade 7: speed = distance / time, balanced and unbalanced forces, friction and air resistance, weight and mass, newtons.

Source: https://olyclass.com/library/science-g7-speed-motion-en/

- Subject: Science
- Level: Grade 7
- Quiz: 16
- Play it free on one screen (projector, TV or whiteboard): https://olyclass.com/library?play=science-g7-speed-motion-en
- Copy and edit it: https://olyclass.com/library?copy=science-g7-speed-motion-en
- Games it plays well in: [Memory Match](https://olyclass.com/classroom-games/memory-match/), [Mystery Picture](https://olyclass.com/classroom-games/mystery-picture/), [Tile Grab](https://olyclass.com/classroom-games/tile-grab/), [Dare Board](https://olyclass.com/classroom-games/dare-board/)

## Questions

1. Which formula gives speed? (distance + time / distance × time / distance ÷ time / time ÷ distance)
   Answer: distance ÷ time
2. A cyclist rides 60 km in 3 hours at a steady pace. What is her speed? (180 km/h / 20 km/h / 57 km/h / 63 km/h)
   Answer: 20 km/h
3. A car travels 150 metres in 10 seconds. What is its speed in m/s?
   Answer: 15 m/s
4. A train moves at a steady 20 m/s. How long does it take to travel 300 m? (15 s / 280 s / 320 s / 6000 s)
   Answer: 15 s
5. When two forces on an object are equal and opposite, we say they are... (balanced / friction / stronger / unbalanced)
   Answer: balanced
6. An unbalanced force can make a moving object speed up, slow down or change direction.
   Answer: True
7. A book rests on a table and does not move. What can you say about the forces on it? (Only one force acts on it / There are no forces / They are balanced / They are unbalanced)
   Answer: They are balanced
8. Which force slows a sliding box as its bottom rubs along the floor? (friction / gravity / magnetism / upthrust)
   Answer: friction
9. Which change would reduce friction between two surfaces? (Adding oil / Adding sandpaper / Making them rougher / Pressing them together harder)
   Answer: Adding oil
10. Air resistance acts on a falling parachutist and slows the fall.
   Answer: True
11. What is the name of the force that pulls objects towards the Earth?
   Answer: gravity
12. About how many newtons is the weight of a 1 kg mass on Earth?
   Answer: About 10 N (9.8 N)
13. An astronaut's mass changes when she travels from Earth to the Moon.
   Answer: False
14. What is the unit of force? (joule / kilogram / metre / newton)
   Answer: newton
15. Which instrument is used to measure a force? (measuring cylinder / newton meter / stopwatch / thermometer)
   Answer: newton meter
16. On the Moon, an object's weight is smaller than on Earth because the Moon's... (air is thicker / friction is greater / gravity is weaker / mass is larger)
   Answer: gravity is weaker