Grade 6 Gravity & Friction worksheet
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How to explain it
- Gravity is a force of attraction between objects that have mass.
- Mass is the amount of matter. Weight is the pull of gravity on that mass.
- Friction slows sliding objects. Rough surfaces like carpet give more friction.
- Air resistance slows light, spread-out objects like feathers. Unbalanced forces change motion.
Example: A puck slides on ice, wood and carpet. Where does it slow down fastest? Rougher surfaces make more friction. Carpet is the roughest. Answer: on carpet
Question 1
A car cruises at a steady 80 km/h on a straight highway. The forces on it are…
- unbalanced: friction is bigger
- zero: no forces act on a moving car
- unbalanced: the engine's push is bigger
- balanced: the engine's push equals friction and air resistance
balanced: the engine's push equals friction and air resistance
Hint: Steady speed in a straight line means the motion isn't changing, so the forces must be balanced.
Question 2
Is the friction helpful or a problem? Tap an item, then tap its basket.
Sort into: 👍 helpful friction · 👎 friction is a problem
- 🩹a blister from a rubbing shoe
- ⛓️a bike chain wearing out
- 🚪a stiff, squeaky door hinge
- ✏️a pencil leaving marks on paper
- 🚗tire treads gripping a wet road
- 🚲bike brakes stopping a wheel
👍 helpful friction: a pencil leaving marks on paper, tire treads gripping a wet road, bike brakes stopping a wheel · 👎 friction is a problem: a blister from a rubbing shoe, a bike chain wearing out, a stiff, squeaky door hinge
Hint: Friction is helpful when we need grip or need to stop. It's a problem when it wears things out, wastes energy or makes things hard to move.
Question 3
In a tug-of-war, the Blue team pulls left with 560 N and the Gold team pulls right with 330 N. What is the net force on the rope?
Pulling force (N) - 0 N (balanced)
- 230 N to the right
- 230 N to the left
- 890 N to the left
230 N to the left
Hint: When forces point in opposite directions, subtract the smaller from the larger. The net force points the way of the bigger force. Equal forces are balanced: the net force is 0 N.
Question 4
How does a parachute slow a skydiver down?
🪂- by making the skydiver heavier
- by increasing air resistance
- by decreasing air resistance
- by turning off gravity
by increasing air resistance
Hint: Air resistance is friction with the air. A big parachute catches lots of air.
Question 5
The Moon's gravity is about 1/6 as strong as Earth's. A rover weighs 840 N on Earth. About how much does it weigh on the Moon?
🌙answer boxN
140 N
Hint: Weight is the pull of gravity. With 1/6 of the gravity, the rover weighs 1/6 as much, so divide its Earth weight by 6.
Question 6
What is gravity?
🍎- a force that only acts on falling objects
- a force made only by magnets
- a push from the air
- a force of attraction between objects that have mass
a force of attraction between objects that have mass
Hint: Every object with mass pulls on every other one. Earth is so massive that its pull keeps us on the ground.
Question 7
On Earth, why does a feather fall more slowly than a rock?
- Air resistance slows the feather much more
- The feather has more mass
- Gravity doesn't pull on feathers
- Gravity pulls light things upward
Air resistance slows the feather much more
Hint: The feather is light and spread out, so the air pushes back on it a lot compared to its weight.
Question 8
What is the difference between mass and weight?
- They are exactly the same thing
- Mass is the amount of matter; weight is the pull of gravity on it
- Mass changes on the Moon, but weight never does
- Weight is the amount of matter; mass is the pull of gravity on it
Mass is the amount of matter; weight is the pull of gravity on it
Hint: Mass is measured in kilograms and stays the same everywhere. Weight is a force, measured in newtons, and depends on gravity.
Question 9
A book rests on a table. Gravity pulls it down. What force balances gravity?
📕- the table pushing up on the book
- air pushing down on the book
- friction pulling it sideways
- nothing; the forces are unbalanced
the table pushing up on the book
Hint: The book isn't moving, so the forces must be balanced. Something must push up as hard as gravity pulls down.
Question 10
An astronaut has a mass of 66 kg on Earth. What is her mass on the Moon?
👩🚀- about 11 kg
- about 396 kg
- 66 kg
- 0 kg
66 kg
Hint: Mass is the amount of matter in an object, so it stays the same everywhere. Weight, the pull of gravity, is what changes on the Moon.
Answer key
- 1. balanced: the engine's push equals friction and air resistance
- 2. 👍 helpful friction: a pencil leaving marks on paper, tire treads gripping a wet road, bike brakes stopping a wheel · 👎 friction is a problem: a blister from a rubbing shoe, a bike chain wearing out, a stiff, squeaky door hinge
- 3. 230 N to the left
- 4. by increasing air resistance
- 5. 140 N
- 6. a force of attraction between objects that have mass
- 7. Air resistance slows the feather much more
- 8. Mass is the amount of matter; weight is the pull of gravity on it
- 9. the table pushing up on the book
- 10. 66 kg
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