Learning Outcomes
 All are able to describe the forces acting
on a sprinter.
 All are able to complete an examination
question to demonstrate knowledge
and understanding.
 Most are able to explain and apply
Newton’s Three Laws to at least two
named sports.
 Some are able to analyse the theory of
Newton’s Three Laws using their own
examples.
Homework
 Watch video clips on projectile motion
on weebly and complete worksheet to
demonstrate understanding for 03.03.15
 Complete exam questions on forces
and Newton’s Law for 10.02.15
 Prepare for revision lesson
Starter Activity
 Complete True and False activity to demonstrate
knowledge gained last week and to introduce forces.
A scalar is a quantity which is describe by
both magnitude and direction.
Weight is the quantity of matter a body
possesses.
Inertia is the reluctance of the body to
move or change its state of motion.
Velocity is the rate of change in distance
or body’s movement per unit of time
Momentum is the amount of motion a
body possesses and is the product of mass
and velocity
Force-time graph: net impulse is positive
when an athlete is accelerating
Force-time graph: a runner is at constant
velocity when the net impulse is negative
A shot putter performs turns to increase
impulse by maximising the time over
which a force is applied.
Starter Activity
 Complete True and False activity to demonstrate
knowledge gained last week and to introduce forces.
A scalar is a quantity which is describe by
both magnitude and direction.
Weight is the quantity of matter a body
possesses.
Inertia is the reluctance of the body to
move or change its state of motion.
Velocity is the rate of change in distance
or body’s movement per unit of time
Momentum is the amount of motion a
body possesses and is the product of mass
and velocity
Force-time graph: net impulse is positive
when an athlete is accelerating
Force-time graph: a runner is at constant
velocity when the net impulse is negative
A shot putter performs turns to increase
impulse by maximising the time over
which a force is applied.
F (vector)
F (mass)
T
F (speed)
T
T
F
T
Exam Q
 Heptathletes are required to complete the 200metre
sprint.
 A 200metre runner must exert a large force in a short
period of time to generate an impulse. Sketch and
label a graph to show the impulse generated during the
acceleration phase of a 200metre race. (3 marks)
Answer
 Heptathletes are required to complete the 200metre sprint.
 A 200metre runner must exert a large force in a short period of
time to generate an impulse. Sketch and label a graph to show
the impulse generated during the acceleration phase of a
200metre race. (3 marks)

 A. X Axis – (time)/milliseconds/seconds
 B. Y Axis – (force)/Newton’s
 C. Shape of graph – negative and positive components of force
shown
 with negative first
 D. Positive impulse clearly larger than negative impulse
 E. Positive and negative (force) labelled
Question
 Explain, in terms of a player moving towards the ball
in tennis, the difference between velocity and
acceleration. (3 marks)
Answer
 Explain, in terms of a player moving towards the ball in tennis,
the difference between velocity and acceleration. (3 marks)

 A. Velocity = rate of change of displacement/displacement ÷






time;
(Not speed, not distance)
B. How fast/quickly player moves towards ball;
C. Acceleration (not speed) = rate of change of velocity/change
in velocity ÷ time (taken to change)/[Vf - Vi] ÷ time/a = !v ÷ t;
D. Push off ground to accelerate (not speed)/change velocity;
E. (Both) have direction/are vectors. 3 marks
Factors affecting a force
 A force can be described as a ‘push or a pull’
When describing a force you must consider:
 Size or magnitude
 Direction of force
 The position of the force
 Activity – five main factors to consider, can you draw
them onto the sprinter?
Forces acting on a sprinter
10
Forces acting on a sprinter
11
Forces acting on a sprinter
Air
resistance
Gravity
Friction
Equal and opposite Ground
Reaction Force
Action force of muscular
contraction
12
Mini plenary
 Use your text book to find out
1. The three factors affecting friction
2. The three factors affecting air resistance
Newton’s First Law: Law of Inertia
A body will continue in a state of rest
or uniform motion unless acted upon by
an external force. A body has a reluctance
to change in its state of motion.
 If a force acts on an object, it will accelerate
in the direction of the force.
 If an object is given an initial velocity and
there are no forces acting on it, the object
will continue along its original path in a
straight line.
Newton’s Second Law: Law of
acceleration
The rate of change of momentum of a
body is proportional to the force causing
it and takes place in the direction in
which the force was applied.
 In sport mass remains constant
therefore mass equates to acceleration.
 The greater the force being exerted on
an object, the faster the object moves.
A big mass (tennis ball)
is harder to accelerate
than a smaller mass
(table tennis ball).
Newton’s Third Law – the Law of action and
reaction
For every action there is an equal
and opposite reaction
 For every force between two objects
there is always an equal but oppositely
directed force.
 The normal reaction force is
the support force exerted upon
an object which is in contact
with another stable object.
Normal
reaction
force
Weight
Application of the theory
 Apply Newton’s three Laws of Motion to the following
situations:
 A high jumper at take off
 A high diver performing a dive
 A gymnast performing a vault
 A football player taking a penalty
Extension: come up with an example of your own to
illustrate your understanding further
Learning Outcomes
 All are able to describe the forces acting
on a sprinter.
 All are able to complete an examination
question to demonstrate knowledge
and understanding.
 Most are able to explain and apply
Newton’s Three Laws to at least two
named sports.
 Some are able to analyse the theory of
Newton’s Three Laws using their own
examples.
All are able to complete an examination question to
demonstrate knowledge and understanding.
 A sprinter uses her calf muscles to push on the blocks at the start of a
run. Explain, using Newton’s laws, how this enables her to accelerate
forwards out of the blocks. 3 marks
 A sprinter uses her calf muscles to push on the blocks at the start of a
run. Explain, using Newton’s laws, how this enables her to accelerate
forwards out of the blocks. 3 marks
 Newton’s 1st law - Sprinter remains in a set position on the
blocks until a force causes him to change his position
 Newton’s 2nd law of motion - if a force is exerted, then this
produces an acceleration in the same direction as the force
(forwards). – sprinter pushes
 Newton’s 3rd law of motion - action and reaction are equal and
opposite in direction.
 • When the sprinter pushes down and back on the ground.
 • The ground pushes up and forward on her.
Plenary activity
 Return to your starter activity and check the work on
forces to see what progress you have made.
 Write either
 a sentence,
 four words or
 draw a diagram
to illustrate your understanding of Newton’s 3 Laws.
Learning Outcomes
 All are able to describe the forces acting
on a sprinter.
 All are able to complete an examination
question to demonstrate knowledge
and understanding.
 Most are able to explain and apply
Newton’s Three Laws to at least two
named sports.
 Some are able to analyse the theory of
Newton’s Three Laws using their own
examples.