Transcript Forces, Gravity and Acceleration

Forces
Gravity and Acceleration
Mr. Monroe
November 8, 2009
A FORCE is a push and a pull on another object.
Balanced Forces will not cause change.
Newton's 1st law says that things will just keep doing
what they are
already doing (same velocity) unless
acted upon by an unbalanced
force.
a.
same direction
b.
same speed
Balanced Forces will not cause change.
Newton's 1st law says that things will just keep doing
what they are
already doing (same velocity) unless
acted upon by an unbalanced
force.
a.
same direction
b.
same speed
Balanced Forces will not cause change because of
INERTIA.
Inertia is the property of matter that resists changes in
motion.
Unbalanced Forces WILL cause change.
Newton's 2nd law says that the amount of
acceleration will depend upon the amount of force that is
applied, and what is trying to be moved.
Force = Mass times Acceleration
Unbalanced Forces WILL cause change.
Newton's 2nd law says that the amount of
acceleration will depend upon the amount of force that is
applied, and what is trying to be moved.
Force = Mass times Acceleration
Force is given in Newtons
Mass is given in Kilograms
Acceleration is given in m/s/s
Man pushes with force of 100 Newtons
Car has mass of 1,500 kilograms
What is acceleration?
Net force of 120
Newtons
Net force of 80 Newtons
Mass of 25
Kilograms
What will be the acceleration of the sled, given the forces of the dogs above.
Net force of 120
Newtons
Net force of 80 Newtons
Mass of 25
Kilograms
What will be the acceleration of the sled, given the forces of the dogs above.
What will be the SPEED of the cart, in 30 seconds, if acceleration is constant?
Gravity is a force.
Gravity pulls everything at 9.8 m/s/s
A cow falls out of an airplane, what is its rate of acceleration,
excluding air resistance?
A cow falls out of an airplane, what is its rate of acceleration,
excluding air resistance?
Gravity is a force that causes ALL things on Earth to fall with
a rate of acceleration of 9.8 m/s/s.
A cow falls out of an airplane, what is its rate of acceleration,
excluding air resistance?
If the cow falls for 45 seconds, excluding air resistance, how
fast will it be plummeting to its end as a burger?
A cow falls out of an airplane, what is its rate of acceleration,
excluding air resistance?
If the cow falls for 45 seconds, excluding air resistance, how
fast will it be plummeting to its end as a burger?
9.8 m/s
45 seconds
---------- x
--------------- = 441 m/second
s
1
A cow falls out of an airplane. It falls at the commonly
accepted acceleration due to gravity, and it fell for 55
seconds, without air resistance. How far did it fall, before it
hit a soft billowy pile of hay, that allowed it to live out its
natural life in peace and tranquility?
A cow falls out of an airplane. It falls at the commonly
accepted acceleration due to gravity, and it fell for 55
seconds, without air resistance. How far did it fall, before it
hit a soft billowy pile of hay, that allowed it to live out its
natural life in peace and tranquility?
The formula that you must work with is
Distance = 1/2 acceleration • time2
A cow falls out of an airplane. It falls at the commonly
accepted acceleration due to gravity, and it fell for 55
seconds, without air resistance. How far did it fall, before it
hit a soft billowy pile of hay, that allowed it to live out its
natural life in peace and tranquility?
The formula that you must work with is
Distance = 1/2 acceleration • time2
Distance = .5(9.8 m/s/s) • 552
A cow falls out of an airplane. It falls at the commonly
accepted acceleration due to gravity, and it fell for 55
seconds, without air resistance. How far did it fall, before it
hit a soft billowy pile of hay, that allowed it to live out its
natural life in peace and tranquility?
The formula that you must work with is
Distance = 1/2 acceleration • time2
Distance = .5(9.8 m/s/s) • 55 seconds2
Distance = 4.9 m/s2 • 3,025 s2
A cow falls out of an airplane. It falls at the commonly
accepted acceleration due to gravity, and it fell for 55
seconds, without air resistance. How far did it fall, before it
hit a soft billowy pile of hay, that allowed it to live out its
natural life in peace and tranquility?
The formula that you must work with is
Distance = 1/2 acceleration • time2
Distance = .5(9.8 m/s/s) • 55 seconds2
Distance = 4.9 m/s2 • 3,025 s2
Distance = 4.9 m/s2 • 3,025 s2
A cow falls out of an airplane. It falls at the commonly
accepted acceleration due to gravity, and it fell for 55
seconds, without air resistance. How far did it fall, before it
hit a soft billowy pile of hay, that allowed it to live out its
natural life in peace and tranquility?
The formula that you must work with is
Distance = 1/2 acceleration • time2
Distance = .5(9.8 m/s/s) • 55 seconds2
Distance = 4.9 m/s2 • 3,025 s2
Distance = 4.9 m/s2 • 3,025 s2
Distance = 14,823 meters, or about 9 miles.
A ball rolls off of a 1.35 meter tall table. How long does it
take it to fall to the ground?
A ball rolls of of a 1.35 meter tall table. How long does it
take it to fall to the ground?
The formula that you must work with is
Distance = 1/2 acceleration • time2
A ball rolls of of a 1.35 meter tall table. How long does it
take it to fall to the ground?
The formula that you must work with is
Distance = 1/2 acceleration • time2
1.35 = 4.9 x t2 (I purposefully left off the labels)
A ball rolls of of a 1.35 meter tall table. How long does it
take it to fall to the ground?
The formula that you must work with is
Distance = 1/2 acceleration • time2
1.35 = 4.9 x t2 (I purposefully left off the labels)
1.35 ÷ 4.9 = t2
A ball rolls of of a 1.35 meter tall table. How long does it
take it to fall to the ground?
The formula that you must work with is
Distance = 1/2 acceleration • time2
1.35 = 4.9 x t2 (I purposefully left off the labels)
1.35 ÷ 4.9 = t2
0.28 seconds = t2
A ball rolls of of a 1.35 meter tall table. How long does it
take it to fall to the ground?
The formula that you must work with is
Distance = 1/2 acceleration • time2
1.35 = 4.9 x t2 (I purposefully left off the labels)
1.35 ÷ 4.9 = t2
0.28 seconds = t2
0.52 sec = time
Isaac Newton
(1642 - 1727)
Every object in a state of uniform motion tends to
remain in that state of motion unless an external
force is applied to it.
Every object in a state of uniform motion tends to
remain in that state of motion unless an external
force is applied to it.
The relationship between an object's mass m, its
acceleration a, and the applied force F is F = ma.
Acceleration and force are vectors (as indicated by their
symbols being displayed in slant bold font); in this law
the direction of the force vector is the same as the
direction of the acceleration vector.
The relationship between an object's mass m, its
acceleration a, and the applied force F is F = ma.
Acceleration and force are vectors (as indicated by their
symbols being displayed in slant bold font); in this law
the direction of the force vector is the same as the
direction of the acceleration vector.
For every action there is an equal and opposite reaction.
1. The elephant and the feather each have the
same force of gravity.
2. The elelphant has more mass, yet both
elephant and feather experience the same force
of gravity.
3. The elephant experiences a greater force of
gravity, yet both the elephant and the feather
have the same mass.
4. On earth, all objects (whether an elephant or
a feather) have the same force of gravity.
5. The elephant weighs more than the feather,
yet they each have the same mass.
6. The elephant clearly has more mass than
the feather, yet they each weigh the same.
7. The elephant clearly has more mass than
the feather, yet the amount of gravity (force) is
the same for each.
8. The elephant has the greatest acceleration,
yet the amount of gravity is the same for each.
1. The elephant and the feather each have the
same force of gravity. FALSE
2. The elelphant has more mass, yet both
elephant and feather experience the same force
of gravity.
3. The elephant experiences a greater force of
gravity, yet both the elephant and the feather
have the same mass.
4. On earth, all objects (whether an elephant or
a feather) have the same force of gravity.
5. The elephant weighs more than the feather,
yet they each have the same mass.
6. The elephant clearly has more mass than
the feather, yet they each weigh the same.
7. The elephant clearly has more mass than
the feather, yet the amount of gravity (force) is
the same for each.
8. The elephant has the greatest acceleration,
yet the amount of gravity is the same for each.
1. The elephant and the feather each have the
same force of gravity. FALSE
2. The elelphant has more mass, yet both
elephant and feather experience the same force
of gravity. FALSE
3. The elephant experiences a greater force of
gravity, yet both the elephant and the feather
have the same mass.
4. On earth, all objects (whether an elephant or
a feather) have the same force of gravity.
5. The elephant weighs more than the feather,
yet they each have the same mass.
6. The elephant clearly has more mass than
the feather, yet they each weigh the same.
7. The elephant clearly has more mass than
the feather, yet the amount of gravity (force) is
the same for each.
8. The elephant has the greatest acceleration,
yet the amount of gravity is the same for each.
1. The elephant and the feather each have the
same force of gravity. FALSE
2. The elelphant has more mass, yet both
elephant and feather experience the same force
of gravity. FALSE
3. The elephant experiences a greater force of
gravity, yet both the elephant and the feather
have the same mass. FALSE
4. On earth, all objects (whether an elephant or
a feather) have the same force of gravity.
5. The elephant weighs more than the feather,
yet they each have the same mass.
6. The elephant clearly has more mass than
the feather, yet they each weigh the same.
7. The elephant clearly has more mass than
the feather, yet the amount of gravity (force) is
the same for each.
8. The elephant has the greatest acceleration,
yet the amount of gravity is the same for each.
1. The elephant and the feather each have the
same force of gravity. FALSE
2. The elelphant has more mass, yet both
elephant and feather experience the same force
of gravity. FALSE
3. The elephant experiences a greater force of
gravity, yet both the elephant and the feather
have the same mass. FALSE
4. On earth, all objects (whether an elephant or
a feather) have the same force of gravity. FALSE
5. The elephant weighs more than the feather,
yet they each have the same mass.
6. The elephant clearly has more mass than
the feather, yet they each weigh the same.
7. The elephant clearly has more mass than
the feather, yet the amount of gravity (force) is
the same for each.
8. The elephant has the greatest acceleration,
yet the amount of gravity is the same for each.
1. The elephant and the feather each have the
same force of gravity. FALSE
2. The elelphant has more mass, yet both
elephant and feather experience the same force
of gravity. FALSE
3. The elephant experiences a greater force of
gravity, yet both the elephant and the feather
have the same mass. FALSE
4. On earth, all objects (whether an elephant or
a feather) have the same force of gravity. FALSE
5. The elephant weighs more than the feather,
yet they each have the same mass. FALSE
6. The elephant clearly has more mass than
the feather, yet they each weigh the same.
7. The elephant clearly has more mass than
the feather, yet the amount of gravity (force) is
the same for each.
8. The elephant has the greatest acceleration,
yet the amount of gravity is the same for each.
1. The elephant and the feather each have the
same force of gravity. FALSE
2. The elelphant has more mass, yet both
elephant and feather experience the same force
of gravity. FALSE
3. The elephant experiences a greater force of
gravity, yet both the elephant and the feather
have the same mass. FALSE
4. On earth, all objects (whether an elephant or
a feather) have the same force of gravity. FALSE
5. The elephant weighs more than the feather,
yet they each have the same mass. FALSE
6. The elephant clearly has more mass than
the feather, yet they each weigh the same.
FALSE
7. The elephant clearly has more mass than
the feather, yet the amount of gravity (force) is
the same for each.
8. The elephant has the greatest acceleration,
yet the amount of gravity is the same for each.
1. The elephant and the feather each have the
same force of gravity. FALSE
2. The elelphant has more mass, yet both
elephant and feather experience the same force
of gravity. FALSE
3. The elephant experiences a greater force of
gravity, yet both the elephant and the feather
have the same mass. FALSE
4. On earth, all objects (whether an elephant or
a feather) have the same force of gravity. FALSE
5. The elephant weighs more than the feather,
yet they each have the same mass. FALSE
6. The elephant clearly has more mass than
the feather, yet they each weigh the same.
FALSE
7. The elephant clearly has more mass than
the feather, yet the amount of gravity (force) is
the same for each. FALSE
8. The elephant has the greatest acceleration,
yet the amount of gravity is the same for each.
1. The elephant and the feather each have the
same force of gravity. FALSE
2. The elelphant has more mass, yet both
elephant and feather experience the same force
of gravity. FALSE
3. The elephant experiences a greater force of
gravity, yet both the elephant and the feather
have the same mass. FALSE
4. On earth, all objects (whether an elephant or
a feather) have the same force of gravity. FALSE
5. The elephant weighs more than the feather,
yet they each have the same mass. FALSE
6. The elephant clearly has more mass than
the feather, yet they each weigh the same.
FALSE
7. The elephant clearly has more mass than
the feather, yet the amount of gravity (force) is
the same for each. FALSE
8. The elephant has the greatest acceleration,
yet the amount of gravity is the same for each.
FALSE
9. Every statement on this page is FALSE
Your job, if you decide to take it.
Your job, if you decide to take it.
The spouse says that the
driver did not see the sign,
and was going way too fast
for conditions.
Spouse says car flew off the cliff, at 50
meters per second.
You and your partner have been called in to see if
the spouse is telling the truth.
Could this have happened as the “witness” says?
35m
45 m
First, how long was the car in the air?
d = 1/2 acceleration • time2
35 m = 1/2 (9.8 m/s/s) • time2
divide both sides by 1/2 acceleration
35
---- = time2
4.9
gives
7.14 = time 2
taking square root of both sides equals
2.67 seconds is time
We now know that
1. The car was in the air for 2.67 seconds.
2. We were TOLD that is was moving at 50 meters/sec.
3. We take a tape measure and see that it actually landed
45 meters from the base of the cliff.
4. We use formula speed = distance ÷ time to see if all
matches up.
s = d ÷ t, distance = speed • time
Distance = 50 m/s • 2.67 seconds.
Distance = 134 meters (NOT 45 METERS), so spouse lied.
You cracked the case, and will be getting your gold shield
as a junior detective :)