Edexcel A Level Physics:復習筆記2.7 Projectiles
Components of Velocity
- The trajectory of an object undergoing projectile motion consists of a?vertical?component and a?horizontal?component
- These need to be evaluated separately
- Some key terms to know, and how to calculate them, are:
- Time of flight:?how long the projectile is in the air
- Maximum height attained:?the height at which the projectile is momentarily at rest
- Range:?the horizontal distance traveled by the projectile
How to find the time of flight, maximum height and range
Problems Involving Projectile Motion
- There are two main considerations for solving problems involving two-dimensional motion of a projectile
- Constant velocity in the horizontal direction
- Constant acceleration in a perpendicular direction
- The only force acting on the projectile, after it has been released, is?gravity
- There are three possible scenarios for projectile motion:
- Vertical?projection
- Horizontal?projection
- Projection?at an?angle
Worked Example
To Calculate Vertical Projection (Free Fall)
A science museum designed an experiment to show the fall of a feather in a vertical glass vacuum tube.
The time of fall from rest is 0.5 s.
What is the length of the tube, L?
Worked Example
To Calculate Horizontal Projection
A motorcycle stunt-rider moving horizontally takes off from a point 1.25 m above the ground, landing 10 m away as shown.
What was the speed at take-off? (ignoring air resistance)
Worked Example
To calculate projection at an angle
A ball is thrown from a point P with an initial velocity u of 12 m s-1?at 50° to the horizontal.
What is the value of the maximum height at Q? (ignoring air resistance)
Exam Tip
In almost every question using the SUVAT equations one component of velocity will have constant acceleration (for example, the vertical component of projectile motion) and the other will have no acceleration (for example the horizontal component of projectile motion when we ignore air resistance).
The trick which you nearly always have to remember is find the common value - time - first, then substitute it into the second part of your calculation.
As long as your working is clear, even if you forget, you are likely to still achieve half marks. But writing good clear Maths and remembering this tip should get you to the end of your calculation - and full marks!
And finally.... don't forget that?deceleration is?negative?as the object rises.
轉載自savemyexams
以上就是關于【Edexcel A Level Physics:復習筆記2.7 Projectiles】的解答，如需了解學校/賽事/課程動態，可至翰林教育官網獲取更多信息。
往期文章閱讀推薦：
全網破防！ALevel CIE數學M1疑似錯題？經濟P2難度飆升？5月6日大考考情分析必看！
A-Level CIE就大規模泄題發布最嚴處罰！哪些考生必須重考？你的成績怎么辦？
翰林AMC8視頻課重磅上線！
國際競賽真題資源免費領取
