Chapter 6- Newton's Second Law of Motion- Force & Acceleration
What is the factor that affects the amount of air resistance experienced by an object?
- speed of object through the air -surface area of object
What is true about freely falling objects?
-They all fall with the same acceleration -The net force acting on them is their weight -Their weight-to-mass ratios are always the same -Their acceleration is g, the acceleration due to gravity
A 100N force is sued to accelerate a large push cart across the floor. What is the force required to accelerate the push cart twice as fast.
200N
What is true about force and acceleration?
A net force acting on an object causes acceleration
Imagine standing on a bathroom scale on two feed and then one foot. Describe the force and pressure exerted in each case.
Force exerted (weight) is the same in both cases. The pressure exerted on the scale doubles when you switch from two feet to standing on one.
What is the equation for pressure when the force is perpendicular to the surface area?
Pressure = force/ area
Define terminal speed and terminal velocity
Terminal speed is the speed at which the acceleration of a fallen object is zero. Terminal velocity is the terminal speed with direction.
During a lab experiment, a net force is applied to an object and the object accelerates. The mass of the object is then doubles, and the net force applied to it also doubles. Describe the object's acceleration.
The both accelerate at the same rate
Describe what causes friction between two solid surfaces?
The friction is due to irregularities in the two surfaces pressed together. Force is needed to move one material up and over the other or to script the irregularities away.
What does it mean for two quantities to be inversely proportional to one another?
When one quantity increases, the other quantity decreases
Circle the letter of each statement related to Newton's second law that is true. a. acceleration is directly proportional to the net force b. the direction of acceleration is the same as the net force c. acceleration is inversely proportional to mass d. net force and mass are always equal
a, b, c
What is the equation that describes Newton's second law of motion?
a= F/m
How is mass and acceleration related?
acceleration is inversely 1/ mass
A 1-kg river rock and a 10-kg small boulder are dropped from the back of a truck at the same time. Identify which rock will struck the ground first.
both strike the ground at the same time
As the area a force acts on increases, the force exerted on each unit of area _____.
decreases
Identify the condition needed for a feather and coin to fall at the same rate.
fall at the same rate in a vacuum
T/F? Friction does not depend on the types of materials in constant with one another.
false
substances that are liquids or gases are also called ___.
fluids
What quantities are related to pressure?
force and area
What describes pressure?
force per unit of area
An object dropped in the air that experiences no air resistance is said to be in ____.
free fall
A ______ is a diagram in which all of the forces acting on an object are shown.
free-body diagram
When an object is in free fall, the only force acting on the object is ____.
gravity
An object accelerated when a net force is applied to it. What describes the conditions that would double the object's acceleration.
halving the mass.
For a constant force, how does it increase in an object's mass affect its acceleration?
increase in the mass will result in a decrease in acceleration.
The acceleration of an object is directly proportional to the net force acting on it. This means that, as the net force acting on the object increases, the acceleration of the object ___.
increases
When using the equation for Newton's second law, if force is measured in newtons, then the unit for acceleration is _____ and the unit for mass is ____.
m/s²; kg
What are the quantities related by Newton's second law
mass, force, acceleration
The combination of forces acting on an object is known as the ___ force.
net
Two shopping carts of equal mass are pushed by two different people, One cart accelerates three times as fast as the other cart. Describe the forces acting on each cart.
net force acts on both carts. net force on cart that accelerated is faster by 3 times greater than the other force.
What describes the unit of pressure known as a pascal?
newtons per square meter
T/F? Friction depends on how much the materials in contact are pushed together.
true
T/F? The acceleration of an object is equal to the net force acting on it divided by the object's mass.
true
T/F? When friction is present, an object can move with constant velocity even when an outside force is applied.
true
What is the type of force that causes acceleration?
unbalanced
When a hockey puck is struck with a hockey stick, an _________ acts on the puck and the puck _____.
unbalanced force; accelerates
What described the forces that are in balance and when an object reaches its terminal speed
weight and air resistance
