Chapter 1
Define a Law.
A general hypothesis or statement about the relationship of natural quantities that have been tested over and over again and has not been contradicted.
Who was the first scientist to discover the concept of inertia?
Galileo
The connection between mass, acceleration, and force is embodied in which Newtons's Law.
Second Law
Acceleration=force/mass
When you step out of your car, the earth pulls you downward. The reaction to this force is what?
You pull earth upward.
The concept of inertia involves?
Mass
Define a Hypothesis.
An educated guess; is a reasonable explanation that is not fully accepted as factual until tested over and over again by experiment.
Define speed
The distance traveled per time
A falling object that reaches terminal velocity continues to have?
Speed
When the lift equals the weight of a helicopter, the helicopter does what?
Hovers in midair.
As a skydiver continues to fall faster and faster through the air her acceleration?
Decreases
What is the Scientific method?
An orderly method for gaining, organizing, and applying new knowledge.
Define Newton's first law.
Any object at rest will stay at rest, any object in motion will stay in motion.
Consider a heavy and light person with the same-size parachutes jumping together from the same altitude. Who will reach the ground first?
The heavy person
It takes the heavier person longer to reach terminal velocity. therefore the heavier person is falling at a greater rate.
The force that directly propels a motor scooter along a highway is that provided by what?
Road
Tires push back on the road, the road pushes back on the tires/.
Push a cart along a track so twice as much net force acts upon it. If the acceleration remains the same, what is a reasonable explanation?
The mass of the cart is doubled when the force is doubled
What is a theory?
Synthesis of a large body of information that encompasses well-tested hypotheses about certain aspects of the natural world.
The equilibrium rule applies to what?
Objects or systems at rest
A car pulling a Trailer accelerates when the gas pedal is pushed to the floor. if the trailer becomes disconnected, the acceleration of the car will?
Increase
Newton's second law tells us that if the mass of something decreases while the force remains the same, then the acceleration will increase.
A soccer ball is kicked at a 30-m/s speed. While being kicked, the amount of force of the player's foot on the ball is
The same as the amount of force on the foot.
Newton's Third law
What is newton's second law?
The acceleration produced by a net force on an object is directly proportional to the net force.
a= f/m
Outline the scientific method.
1.) Observe
2.) Question
3.) Predict
4.) Test predictions
5.) Draw a conclusion
Define velocity.
The speed of an object and specification of its direction of motion.
In one instant an object in free fall has a speed of 40 m/s. its speed one second later is?
50 m/s
we assume the object is falling downward.
Which exerts more force, the earth pulling on the moon, or the moon pulling on the earth?
Both forces are the same.
What is Newton's third law?
Whenever one object exerts a force on a second object, the second object exerts and equal and opposite force on the first.