Projectiles Launched at an Angle
An angled launch gives both directions a starting velocity, so flight time, greatest height and range all come from the same two lists. The symmetry of the path is a check on the answer rather than an extra rule.
What a learner can do afterwards
- Resolves the launch velocity, then gets the time of flight from the vertical motion alone
- Finds the range from the horizontal component and that time, without quoting a range formula
- Explains why 45 degrees gives the longest range on level ground but not from a cliff top
1 · Read
An angled launch starts with one move: split the launch velocity into u times cos sideways and u times sin upward. A ball kicked at 20 metres per second at 30 degrees starts with about 17.3 sideways and exactly 10 up. Everything after that is the two motions routine you already know.
Flight time comes from the vertical motion alone, and range is the horizontal part times that time, with no range formula quoted. Launch at 19.6 metres per second at 30 degrees: upward is 9.8, so the climb takes 1 second and the flight takes 2. Sideways is about 17, so the range is about 34 m. Greatest height is upward squared over 2 g: 9.8 squared over 19.6, which is 4.9 m.
On level ground 45 degrees wins because it balances climb against cruise, splitting the launch evenly between up and sideways. From a cliff top the fall runs longer than the climb, so extra upward tilt pays off and the best angle drops below 45 degrees.
Horizontal acceleration is zero, so the sideways part cruises untouched while gravity only ever acts vertically. On level ground use symmetry as a check: climb time equals fall time.
Split the launch, take time from the vertical, and multiply sideways speed by that time.
2 · Watch
Take it off screen
Where it sits
This opens up
Nothing builds on it yet.
Where this leads
Jobs that lean on this skill. Follow one to see everything it is built on.
8 questions wait behind this lesson, each with its answer explained. Every answer feeds the sky: stars light as they are learned, and dim when it is time to come back.