1. Falling down
Physics On the Road
Lesson 8

2. LI…
Describe free fall.
Use kinematic equations to
make predictions
Explain parabolic projectile
motion.

3. Free fall

4. Gravity is uniform acceleration
 Galileo first
proposed the idea
that all objects fall
with uniform
acceleration.
 He proved it by
rolling balls down
slopes
 It is an idea with far
reaching
implicationsGravity accelerates all
objects on Earth at a rate
of 9.8 ms-2

5. Air resistance
 Why doesn’t it look
like all objects fall at
the same rate.
 Gravity is not the
only force acting.
 Air resistance acts
against motion.
The air resistance depends upon size,
shape but mostly speed.

6. Falling down
 Describe a parachute jump using a
velocity time graph.
time
velocity

7. Still falling down
 Explaining a parachute jump
 Use the idea of forces
time
velocity
w
w
w
f
w
f
w
f

8. Ignore air resistance - constant acceleration
∆v
∆t
∆t
t=0
2∆v
If you ignore air resistance falling
objects gain speed at the same
rate.
They accelerate at Earth at a rate
of 9.8 ms-2.
Q1. How far will a coin fall in 5
seconds?
0 ms-1
9.8 ms-1
19.6 ms-1

9. Sideways makes no difference
∆v
∆t
∆t
t=0
2∆v
0 ms-1
9.8 ms-1
19.6 ms-1
∆v
2∆v
9.8 ms-1
19.6 ms-1

10. Changing velocity in a parabolic path -vectors
v
∆v
v
v v
v
v
Due to gravity
v
∆v
new
v
v
∆vnew
v

12. Demonstrate Your
Understanding
Explain why this trick is
not as dangerous as it
looks.
EXTENDED ANSWER
TASK
Use diagrams
Use principles
Use vectors
Use calculations