forces acting on objects moving and stopping mechanisms newtons f= ma 9.8meters/sec 2 w= mg kinetic...
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Forces Acting On Objects
Moving and Stopping Mechanisms
Newtons
f= ma
9.8meters/Sec2
w= mg
Kinetic Friction
Nature of MassMass is a Fundamental Property of Matter
1,000 Cubic Centimeters of Water 1 Kilogram
Mass=
View of Africa and Saudi Arabia from Apollo 17. Probably the most requested picture of the Earth, this picture was taken by the Apollo 17 astronauts as they left earth orbit en route to the Moon. Taken on Dec. 7, 1972, it was the first time that the trajectory of an Apollo mission enabled a view of the south pole.
Gravity is force that causes all objects
(matter) to accelerate towards each other
At a constant rate and with a force proportional to their Mass
View of Africa and Saudi Arabia from Apollo 17. Probably the most requested picture of the Earth, this picture was taken by the Apollo 17 astronauts as they left earth orbit en route to the Moon. Taken on Dec. 7, 1972, it was the first time that the trajectory of an Apollo mission enabled a view of the south pole.
Objects on the Earth’s Surface accelerate
down at a rate =
9.8 Meters per Second2
All Objects (Matter) Exert a Gravitational Force On One Another
Proportional to Their Mass
Gravity is the Weakest of the 4 Natural Forces
Weight Gravity’s Effect on Mass
Weight is a Force measured in Newtons Magnitude: Relative to the MassDirection: Center of the Earth
Weight = Mass x Acceleration of Gravity
9.8 (Newtons) =1 (kg) 9.8(Meters/Sec2)
W(Newtons) = m (kg) g(Meters/Sec2)
(W) Weight = 5 kg or 49 Newtons
fsF
W= mg
M1
Spring Scale
Weight is a Force Caused by Gravity Acting on the
Mass of an Object
49 Newtons = 5kg x 9.8m/s/s
Weight = Mass x Gravity
N
Stamp Issued by Germany on Jan. 14, 1993, on his 350th birthday
Image Courtesy of University of St.Andrews, Turnbull Server
Newton Provided Insights Into the Nature of Forces
Let’s Look at a Pair of Balanced Forces Acting on a Robot Resting on the Floor
Because the Floor Pushes Up with the
SAME Force
The Force of Gravity Acts to Accelerate This
Chassis Towards the Earth’s Center
The Chassis is undergoing an Acceleration, but it is Not Moving
Newton’s 1st Law An object with no net force acting on it moves
with constant velocity. Force: 20 NewtonsForce: 20 Newtons
Same Force in Opposite Directions
There is no NET force on the system and the machines remain stationary
Velocity = 0
Newton’s 2nd Law
The acceleration of a body is directly proportional to the net force acting on it and
inversely proportional to its mass.
Robot Mass = 5 Kilograms
Acceleration = 4 meters/sec2
Tractive Force = 20 Newtons
Force = Mass x Acceleration20N = 5kg x 4m/s2
Build Newton’s Cart using the GEARS-IDS components and
experiment with Newton’s second law
f force= m mass a acceleration
Newton’s 2cd Law
Pulley
Newton’s Cart
Mass
Force Experiment with masses and forces, and their affect on acceleration
Using Newton’s Cart1.) Set the System Up on a High Flat Table
Pulley
Cart 2.) Connect a Masons String from the Cart Through the Pulley
3.) Attach a Weight (Force) to the end of the Pulley Side of the Line
4.) Place a Known Mass on the Cart
Note: Separate the Cart and Pulley by 2x Table Height
5.) Allow the Weight to Drop and Time the Speed of the Cart Over a Known Distance
Calculate the Acceleration of the Cart
TT
DCa 2
Where:
Ca= Acceleration of the Cart in meters/sec/sec
D = Distance Covered in meters
T = Time in seconds
Newton’s Third Law When one object exerts a force on a second object, the
second exerts a force on the first that is equal in magnitude but opposite in direction.
The rotating wheels push against the floor and propel the robot forward and
the floor backwards
Floor Momentum = mass x velocityFloor Momentum = 15 kg x 5 mps = 75
Robot Momentum = mass x velocity Robot Momentum = 5 kg x 15 mps = 75
Floor Board Rests on Frictionless
Bearing