Newton’s laws
By: Emma and César
Newton’s First Law Of Motion
Definition:
Every object in a state of uniform
motion tends to remain in that
state of motion unless an
external force is applied to it.
Activity
1: Body At Rest
In this experiment you will learn
about inertia. In it, you will try to
remove a card board from under
an object without moving the coin
on top.
 Materials
You will need the following items for this
experiment
 A cup
 A coin
 A piece of card board
Procedure
1. Place the piece of card board on top of a
cup.
2. Put the coin on top of the piece of card
board.
3. Quickly (and in one smooth motion) flick
the piece of card board from between the
coin and cup.
4. Write down what happens.
2:
And they
are off !!!
Activities
In this experiment you will
discover how Newton’s First
Law works by conducting a
race with two jars.
Materials
You will need the
following items for this
experiment:
• two identical jars with
lids (either plastic or
glass jars)
• flour or sand to fill one
of the jars
• iron filings or small
lead pellets to fill one of
the jars
• two identical, empty
three-ring binders (at
least 2.5” in width)
• a measuring tape
Procedure
1. Fill one jar with flour or sand. Pack it tightly.
2. Fill the other jar with iron filings or small lead pellets. Again, fill it
tightly.
3. Put lids on both of the jars. Lids should be on tight.
4. Place both three-ring binders next to each other on a wooden or tile
floor. Place each jar on
its side and release both from the top of the “ramps” at exactly the
same time.
5. In the Table below, record how far each jar rolled. Do not measure
the binder itself, just the
distance from the end of the binder to where each jar actually
stopped.
6. Repeat Steps 3-4 for each of the surfaces listed on the Table.
7. Fill in the Table with your results for each race.
Newton’s Second Law Of Motion
Definition : second law of
motion the rate of change of
momentum is proportional to
the imposed force and goes in
the direction of the force
Activity 1: pulling car
 Pass a piece of string with a mass hanging on one end over a pulley. Attach the
other end to the trolley so that, when the mass is released, it causes the trolley
to accelerate. Choose a length of string which allows the mass to touch the
ground when the trolley is about two thirds along the bench length.
 Fit the trolley with a double segment black card. Clamp the light gate at a height
to allow both segments of the card to interrupt the light beam when the trolley
moves through the gate. Measure the width of each segment with a ruler and
enter the values into the data-logging software. Connect the light gate via an
interface to a computer programmed.
Configure the program to obtain measurements of acceleration derived from the
double interruptions of the light beam by the card. The program will require the
dimensions of the card. The internal calculation within it involves using the
interruption times for the two segments to obtain two velocities. The difference
between these divided by the time between them yields the acceleration.
Procedure
Data collection
 A: Pull the trolley back so that the mass is raised to just below the pulley. Position the light gate
so that it will detect the motion of the trolley soon after it has started moving. Set the software to
record data. Release the trolley. Observe the measurement for the acceleration of the trolley.
 B:Move the light gate about 20 cm further along the table.
Repeat the measurement, releasing the trolley from the
same point as before. Observe the we measurement and
compare it with the first.
C:Repeat this process several times until the light gate is as near as it can
be to the pulley, while still allowing the trolley to pass through.
Activity2: Pulling
If you want to calculate the
acceleration, first you need to
modify the force equation to
get a = F/m. When you plug in
the numbers for force (100 N)
and mass (50 kg), you find that
the acceleration is 2 m/s2.
Notice that doubling the force
by adding another dog doubles
the acceleration. Oppositely,
doubling the mass to 100 kg
would halve the acceleration to
2 m/s2.
If two dogs are on each
side, then the total force
pulling to the left (200 N)
balances the total force
pulling to the right (200
N). That means the net
force on the sled is zero,
so the sled doesn’t move.
Newton's
Third Law
Of
Motion
Definition
Newtons third law of motion: