3. Newton’s Contributions to Science and Math
Light is composed of a
Laws of Motion
Theory of Gravitation
4. Newton’s First Law (Inertia)
Newton's first law of motion states that an
object at rest remains at rest and an object in
motion remains in motion with the same
velocity unless acted upon by an unbalanced
6. If objects in motion tend to stay in motion, why
don’t moving objects keep moving forever?
Things don’t keep moving forever because there’s
almost always an unbalanced force acting upon
A book sliding across a table slows
down and stops because of the
force of friction.
If you throw a ball into the air it will
eventually slow down and fall
because of the force of gravity.
8. Four types of friction:
• Sliding friction: ice skating
• Rolling friction: bowling
• Fluid friction (air or liquid): air or water resistance
• Static friction: initial friction when moving an object
What is the unbalanced force that acts on anWhat is the unbalanced force that acts on an
object in motion?object in motion?
11. Newton’s Second LawNewton’s Second Law
Force = Mass x AccelerationForce = Mass x Acceleration
Force is measured in NewtonsForce is measured in Newtons
Acceleration of Gravity = 9.8 m/sAcceleration of Gravity = 9.8 m/s² (32 ft/s(32 ft/s²))
Weight (force) = mass x gravityWeight (force) = mass x gravity
Moon’s gravity is 1/6 of the Earth’s
If you weigh 420 Newtons on earth, what will you
weigh on the Moon?
Ans: 70 Newtons
If your mass is 41.5Kg on Earth what is your mass
on the Moon?
12. Falling Objects: Humans
Terminal Velocity = 120 mph
= 176 ft/sec
Acceleration Gravity = 9.8 m/sec²
= 32 ft/sec²
F = ma
= 68 kg (150 lbs.) x 9.8m/sec² = 668 Newtons
1 sec 32 ft/sec
2 sec 64 ft/sec
3 sec 96 ft/sec
4 sec 128 ft/sec
5 sec 160 ft/sec
6 sec 176 ft/sec – Terminal Velocity
Terminal velocity is the highest velocity attainable by an object in
free fall. It occurs once the sum of the drag force (friction) Fd and
buoyancy equals the downward force of gravity FG acting on the
object. Since the net force on the object is zero, the object has zero
18. Consider hitting a baseball with a bat. If we
call the force applied to the ball by the bat the
action force, identify the reaction force.
(a) the force applied to the bat by the
(b) the force applied to the bat by the ball
(c) the force the ball carries with it in
(d) the centrifugal force in the swing
Newton’s First Law:
Objects in motion tend to stay in motion and
objects at rest tend to stay at rest unless acted
upon by an unbalanced force.
Newton’s Second Law:
Force equals mass times acceleration (F = ma).
2nd law applied to Gravity: Weight = mass x 9.8
m/s² or 32 ft/s²
Newton’s Third Law:
For every action there is an equal and opposite