PS-5 Test Review
Questions 1 & 2
Distance – 60m/ magnitude only
Displacement 10 m east/ magnitude
and direction
Question 3
Speed- distance an object moves per
unit of time
Velocity- speed with direction
V = d/t
Questions 4, 5, & 6
They are rates as they measure a
change in distance over time
Instantaneous
average
Question 7
speed- 30 m/s 50 km/ hr
Velocity- 30 m/s west 50 km/hr north
Question 8 & 9
135 km/ 7 hrs = 19.3 km/hr north
D = 25 m/s x 6 s = 150 m
Question 10
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Question 11 & 12
Rate of change in velocity
It does not have a constant velocity
as it is constantly changing direction
It is accelerating as it’s velocity is
changing
Questions 13 & 14
A = 15 km/hr/ 1s = 15 km/hr/s
Speed up, slow down, change
directions
Questions 15 and 16
40km/hr – 0km/hr / 5s = 8km/hr/s
50km/hr – 0km/hr / 5s = 10km/hr/s
Car B accelerates fastest
1st row- no motion, constant velocity
2nd row- constant velocity, positive
acceleration
3rd row- positive acceleration,
negative acceleration
Questions 17 & 18
“g” = 9.8m/s2 and is acceleration due
to gravity
9.8 x 2 = 19.6 m/s
Questions 19 & 20
Newton’s 1st law defines inertia as it
describes an object’s resistance to
change in motion
Inertia is resistance to change in
motion
Example: a car crash
Questions 21 & 22
A force is a push or a pull and is
measured in Newtons
Balanced force- net force of 0,
objects’ motion does not change
Unbalanced force- net force that
accelerates an object
Net force- the sum of all forces acting
on an object
Question 23
The acceleration of an object is
dependent on the force applied and
the mass of the object.
To accelerate an object the force must
be applied in the same direction as
the acceleration.
Questions 24 & 25
F = 1500kg x 2.5 m/s2 = 3750N
M = 500N / 2.0 m/s2 = 250 kg
Question 26
Mass is the amount of matter in an
object. It is constant and is measured
in kg
Weight is the measure of the pull of
gravity on an object. It is a force and
is measured in Newtons.
Questions 27 & 28
W = mass x 9.8m/s2 ( W = mg)
M = weight / 9.8m/s2 (M = w/g)
Inertia is NOT dependent on gravity
because inertia is determined by
mass and mass is a constant.
Questions 29 & 30
Gravity is the force of attraction
between all objects in the universe.
Gravitational attraction depends on
the mass of the 2 objects and the
distance between them
There is not enough mass
Question 31
For every action there is an equal and
opposite reaction.
Question 32
The swimmer pushes on the water
and the water pushes back
The ball pushes on the wall and the
wall pushes back.
The diver pushes down on the raft
and the raft pushes back.
The person pushes on the wall and
the wall pushes back.
Questions 33-35
Air resistance pushes up as gravity
pulls down.
Friction is the force that opposes
motion between 2 objects that are
touching.
An object in free fall has no other
force acting on it but gravity.