Newton's 3 Laws

1. Unbalanced Forces Notes
#1
Newton’s 1st law! Objects in motion...

2. Mass resists acceleration

Example
 Full shopping cart vs. empty shopping cart
 The greater the mass the more force it takes
to accelerate the object

Acceleration is inversely proportional to
mass
 Acceleration ~
1
mass
As the denominator
increases the whole
quantity decreases

3. Ten times as much

4. Newton’s Second Law
The acceleration produced by the force
on an object is directly proportional to
the magnitude of the net force, is in the
same direction as the net force and is
inversely proportional to the mass of the
object
 Mathematically:
acceleration~ net force
mass


5. nd
2
Newton’s
Law in
Mullisen’s words...

The harder you push, the faster it
accelerates – BUT – if it’s massive, it
doesn’t accelerate as much.

Acceleration = How hard you push
How massive it is
acceleration = net force
mass

6. Baby Hippo Physics

You throw a baby hippo upward with a force of
1000 Newtons. The baby hippo’s mass is 500 kg
Acceleration ? = 1,000 newtons up
500 kilograms
Answer: 2 m/s/s
From the beginning of your throw to the end of your
throw (which took 1 second), the baby hippo
accelerated from 0 m/s to 2 m/s


7. Baby Hippo Physics
Now you strap the baby hippo to a
rocket. The rocket burns for 12
seconds, and propels the baby hippo
with a force of 3,000 Newtons.
 Acceleration = 3,000 N
500 kg
 Answer: a = 6 m/s/s
 Every second the rocket burns, the baby
hippo goes 6 m/s faster. After 12
seconds, he’s going 72 m/s (161 mph)


8. Baby Hippo Physics
Now you throw the baby hippo’s mom upward with
a force of 1,000 Newtons. Her mass is 4,500 kg.
Acceleration ? = 1,000 newtons up
4,500 kilograms
Answer: a = .22 m/s/s

From the beginning of your throw to the end of your
throw (which took 1 second), the mommy hippo
accelerated from 0 m/s to .22 m/s

9. Newton’s 3rd Law of Motion
For every action there is an equal and
opposite reaction.
 Examples:

 You jump off a small boat.
 Oxygen tank in outer space.
 You sitting in your chair.
 JetLev Water Rocket Pack