Grade 6 · Science · Unit 4 of 8
Forces in Interactions
Pushes, pulls, tension and reaction
What your child practises
External forces (applied, friction, elastic) and internal forces (tension, compression, shear, torsion), and that every action force has an equal and opposite reaction force.
Alberta Curriculum learning outcome: 6E 1.1, 6E 1.3 · internal and external forces, tension, compression, shear, torsion, friction, and action and reaction forces
Sample questions
A taste of this unit. In the app, questions change every time and get easier or harder to match your child.
Question 1
Pulling on a rope or string creates which force?
- Torsion
- Compression
- Tension
Show answer
Tension
Hint: Tension stretches and pulls.
Question 2
A force that opposes the movement of surfaces that touch is…
- friction
- thrust
- tension
Show answer
friction
Hint: Friction slows a sliding sled.
Question 3
For every action force there is…
- no other force
- an equal and opposite reaction force
- a smaller force always
Show answer
an equal and opposite reaction force
Hint: This is Newton's third law.
Question 4
A force that twists an object is…
- shear
- compression
- torsion
Show answer
torsion
Hint: Wringing out a towel twists it.
Question 5
When air rushes out of a balloon in one direction, the balloon moves in the opposite direction. Why?
- The air is lighter than the balloon
- The air pushes back on the balloon (action and reaction)
- The balloon floats in the air
Show answer
The air pushes back on the balloon (action and reaction)
Hint: The balloon pushes the air, and the air pushes the balloon.
Question 6
A skater pushes off a wall and glides away. Which force acts on the skater?
- Nothing pushes the skater
- Only gravity acts
- The wall's reaction force on the skater
Show answer
The wall's reaction force on the skater
Hint: The skater pushes the wall, so the wall pushes back.