Table of contents | |
Freefall | |
Terminal Velocity | |
Exam Tip | |
Solved Example |
The force of gravity on an object is called its weight. If you are asked to name this force, use this word: don't call it 'gravity', as this term could also mean gravitational field strength, and so might be marked wrong. Additionally, remember to identify air resistance as the upwards force on a falling object. This force gets larger as the object speeds up, but the weight of the object stays constant. Don't confuse 'air resistance' with 'air pressure' - these are two different concepts!
Part (a)
(i) The weight of an object is the force of gravity which acts on it.
(ii) The weight force is due to the Earth's gravitational pull on the object, so weight is due to gravityPart (b)
When something falls, initially it accelerates.
(ii) The resultant force on the object is very large initially, so it accelerates
(iii) This is because there is a large unbalanced force downwards (its weight) - the upward force of air resistance is very small to begin withPart (c)
The faster it falls, the larger the force of friction which acts on it.
(i) The force of air resistance is due to friction between the object's motion and collisions with air particles
(ii) Air particles try to slow the object down, so air itself produces a frictional force, called air resistance (sometimes called drag)Part (d)
Eventually it falls at a steady speed when the force of friction equals the force of gravity acting on it.
(i) When the upwards air resistance grows enough to balance the downwards weight force, the resultant force on the object is zero
(ii) This means the object isn't accelerating - rather, it is moving at a steady (terminal) speed
124 videos|149 docs|37 tests
|
|
Explore Courses for Grade 10 exam
|