mechanical · 22 minutes · Official OETT Aligned
Falling Objects
How gravity and air affect a fall
What to know
- gravity: the downward pull
- weight and falling speed
- air resistance: air slowing an object
A heavier object does not always land first. Look for what the question says about air resistance.
The core rule
Without air resistance, objects dropped from the same height at the same time land together.
Gravity makes falling objects speed up. Without air resistance, their weight does not change how quickly they speed up. Air can slow a wide, flat object more than a compact one. That is why a flat sheet of paper falls more slowly than the same paper crumpled into a ball.
Worked examples
Example 1: easy
Two compact metal balls dropped from the same height land together if air resistance is ignored.
- Both balls are dropped from the same height at the same time. Ignore air resistance.
- Gravity speeds them up equally, so they land together.
Without air resistance, weight does not change the fall time.
Example 2: medium
A flat paper sheet falls slower than a crumpled sheet because drag differs.
- Crumpling paper changes its shape, not its weight.
- The smaller shape meets less air resistance and usually lands sooner.
The difference comes from the air slowing the flat sheet more.
Example 3: hard
Compare a dense small tool and a broad light panel only after the prompt states whether air resistance is ignored.
- Check whether the question includes air resistance.
- Without it, compare starting height and downward motion. With it, also consider shape and how strongly the air slows each object.
You need the stated conditions before deciding which object lands first.
Common mistakes
Heavier objects always fall faster.
Weight alone does not decide the fall time. Check the height, starting motion, and whether air resistance is included.
Put it into practice
Use guided explanations, check your answers, and try a new variation.