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Who was the first person to label forces as a push or pull on an object?
Newton
When would you see force increase?
With an increase in acceleration or mass.
What is friction
Contact forces that move against each other.
How did Galileo test Aristotle's theories of gravity?
Balls on a wooden ramp.
When does air resistance increase?
When surface area increases.
Give an example of a contact force:
When one system touches another, Baseball and a bat.
What is inertia? What would an example of an object with a greater inertia be?
Describes property of matter, greatest push or pull
What is the difference between balanced and unbalanced forces?
Balanced cancel each other out, Net quantity is 0, No increasing movement
When would an object not be affected by freefall? What is free fall?
When forces are balanced,objects falling to gravity alone
Why are hot air balloons floating at a constant altitude not in free fall?
Forces on the balloons are balanced
What is a force field? Give examples.
Forces that act between objects that do not touch: gravitational, magnetic, and electrical
What two ever-present forces affect all motion on the earth?
Both friction and gravity affect all motion on the earth.
How do weight, air resistance, and friction look in a diagram?
Weight: To the center of the earth (from mass)
Friction: On surface resisting
Air resistance: Drag (pulling against)
What is the SI unit of force, what is it's symbol. State the second law of inertia.
Newton, F, F=MA
Give 2 examples of different types of forces
Contact and Field
Give an example of static, rolling, kinetic, and and fluid friction.
Static: Object stopped on a hill
Rolling:Tire
Kinetic: Going down a hill
Fluid: Swimming
A farmer pulls on his mule with a 300 N of force to the right. The ground exerts a reaction force to the mule's resistance of 300 N to the left. What is the net force on the mule system? What is the acceleration
0, they are equal in magnitude but opposite in direction, no acceleration.
A mountain climber falters on a steep slope and slides down until his safety harness catches, pulling his rope taut. Why does he stop sliding?
The tension exceeds the force of gravity by pulling the mountain climber down the slope. Friction slows motion.
A piano suspended from a rope that goes through a pulley begins to fall. What is the largest force acting on the piano?
Gravity, the piano is accelerating in that direction
What is the weight in Newtons of a 2.45 kg laptop computer?
w=mg
24N
Classify gravity and friction. Discuss how they are different.
Gravity is a force field (and also a fundamental force) while friction is a contact force. Friction merely resists motion, acting opposite to the relative motion of two systems in contact. Gravity has the ability to accelerate an object.
Describes how a parachute works:
Air resistance is a form of drag. As a falling objects' speed increases, drag on the object increases, exerting a force opposite to the fall of its direction. The purpose of a parachute is to slow a falling person through drag.
1- the law of inertia, states that objects at rest remain at rest and objects in motion continue moving in a straight line at a constant velocity unless acted on by an outside force
2- Force = mass x acceleration
3- For every action there is an equal by opposite reaction
If all objects exert gravitational attraction on each other, then why doesn't all matter clump together.
Though gravity is a basic property of all matter, even large objects don't exert enough gravitational attraction to overcome friction and other external forces, allowing objects to come together.
You drop a 30g pebble down a well. You hear a splash 2.7s later. Ignoring air resistance, how deep is the well?
= 36m