Physics Chapter 11: Motion Flashcards

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Questions and Answers

What is the velocity of an airplane flying at 635 km per hour at an altitude of 35,000 m over Kansas?

635 km/h

This cannot be determined without further information about its direction. (correct)

16 m/min

35,000 m/s

What is the SI unit for speed?

change in v/t

mph

ft/s^2

m/s (correct)

On a speed-time graph, what does a line with a negative slope indicate?

not moving

slowing down (correct)

traveling at a constant speed

speeding up

What is the combination of all of the forces acting on an object called?

net force Signup and view all the answers

If the net force acting on a stationary object is zero, what will happen to the object?

remain at rest Signup and view all the answers

If the net force on an object is zero, then the object has?

balanced forces Signup and view all the answers

A tug-of-war that results in one team pulling the other across the line is an example of?

unbalanced forces Signup and view all the answers

Which of the following best illustrates balanced forces?

a stretched rubber band being held between two hands Signup and view all the answers

Which of the following statements is true?

Frictional forces are greatest when both surfaces are rough Signup and view all the answers

An object is in motion when?

the object changes position relative to a stationary reference point Signup and view all the answers

Which straight-line acceleration indicates an increase in speed?

4 m/s^2 Signup and view all the answers

Which is an example of balanced forces acting on an object?

a leaf lying on the grass Signup and view all the answers

An object that changes position relative to a reference point is?

in motion Signup and view all the answers

Average speed can be represented by the mathematical expression?

distance/time Signup and view all the answers

The _____ of an object consists of its speed and direction.

velocity Signup and view all the answers

The average speed of a runner who runs 500 m in 1.6 min is?

5.2 m/s Signup and view all the answers

A car moving at an average speed of 55.0 mi/h for 4.25 h has traveled?

234 mi Signup and view all the answers

On a distance vs time graph of an object's motion, distance is usually?

the dependent variable Signup and view all the answers

A pitcher throws a baseball to home plate, a distance of 60.5 ft. The ball reaches home plate in 0.63 s. What is the velocity of the ball?

96 ft/s towards home plate Signup and view all the answers

When the motion of an object is shown by a straight line on a distance vs time graph with distance on the y-axis, the slope of the line is the?

speed Signup and view all the answers

On a bus traveling north at 20.0 m/s, a child stands up and walks toward the back of the bus at 1.3 m/s. What is the child's resultant velocity?

18.7 m/s north Signup and view all the answers

Speeding up, slowing down, and changing direction is best described as?

acceleration Signup and view all the answers

When centripetal acceleration occurs, an object?

changes direction Signup and view all the answers

The equation for finding average acceleration for straight-line motion is?

final velocity - initial velocity/time Signup and view all the answers

Moving from 0 m/s to 25 m/s in 8.0 s equals an average acceleration of?

3.1 m/s^2 Signup and view all the answers

A cyclist is traveling at an initial speed of 10.0 m/s. She accelerates at a rate of 0.500 m/s^2. What is her final speed after 9.0 s?

14.5 m/s Signup and view all the answers

Peter runs in a constant direction on a straight road. The velocity vs time graph of Peter's motion shows a straight line with a negative slope. What does the line tell you about Peter's speed?

it is decreasing Signup and view all the answers

When velocity changes by the same amount over each time interval, acceleration is?

constant Signup and view all the answers

On a velocity vs time graph, what shows the value of the acceleration?

the slope of the line Signup and view all the answers

A cheetah can accelerate at up to 6.0 m/s^2. How long does it take for a cheetah to speed up from 10.5 m/s to 12.2 m/s?

0.28 s Signup and view all the answers

What happens when a car slows down and velocity changes?

negative acceleration Signup and view all the answers

Net force is?

the combination of all the forces acting on an object Signup and view all the answers

An object experiencing balanced forces?

has a net force of zero Signup and view all the answers

Which is an example of static friction?

pushing a box that is at rest Signup and view all the answers

Which is not an example of sliding friction?

rolling a ball across a desk Signup and view all the answers

The friction between objects that are stationary is called?

static friction Signup and view all the answers

On a distance vs time graph, the line of an object at rest is a?

flat line with a slope of zero Signup and view all the answers

The difference between speed and velocity is that velocity includes?

direction Signup and view all the answers

An example of helpful friction is?

writing on paper with a pen Signup and view all the answers

Friction is defined as the?

force that opposes motion between two surfaces that are touching Signup and view all the answers

Which is an example of kinetic friction?

friction between a car's windshield and the air as you drive into the wind Signup and view all the answers

When an object slows down, its acceleration is?

negative Signup and view all the answers

Displacement?

All of the above Signup and view all the answers

The force of gravity, the electromagnetic force, the strong nuclear force, and the weak nuclear force are considered?

fundamental forces Signup and view all the answers

On a speed vs time graph, constant acceleration is represented by a?

straight line Signup and view all the answers

The friction between the bristles of your toothbrush and the surfaces of your teeth is an example of?

helpful friction Signup and view all the answers

Study Notes

Motion and Forces

An airplane's velocity cannot be determined without its direction, even if its speed is given as 635 km/h.
The SI unit of speed is meters per second (m/s).
A negative slope on a speed-time graph indicates an object is slowing down.
The net force acting on an object is the combination of all forces acting on it.

Types of Forces

If the net force on a stationary object is zero, it will remain at rest.
Balanced forces result in a net force of zero, while unbalanced forces cause an object to accelerate in the direction of the stronger force.
An object in motion relative to a reference point is considered in motion.

Speed and Velocity

Average speed is calculated as distance divided by time (distance/time).
Velocity includes both speed and direction.
An increase in speed is indicated by positive acceleration.

Acceleration

Average acceleration is calculated with the formula: (final velocity - initial velocity) / time.
Constant acceleration occurs when velocity changes by the same amount over equal time intervals.
Negative acceleration occurs when an object slows down.

Graphs and Motion

In distance vs. time graphs, distance is the dependent variable, typically plotted on the y-axis.
The slope of a distance vs. time graph indicates speed, while the slope of a velocity vs. time graph indicates acceleration.
An object at rest has a flat line with a slope of zero on a distance vs. time graph.

Friction

Static friction occurs between stationary objects, while kinetic friction is when objects are in motion.
Helpful friction allows us to write on paper, while undesirable friction can wear out car tires.
Friction acts as a force opposing the motion between two surfaces in contact.

Displacement and Forces

Displacement involves the change in position of an object and must be in a specific direction.
Fundamental forces include gravity, electromagnetic, strong nuclear, and weak nuclear forces.
Friction is defined as the force that opposes motion between two surfaces that are touching.

Important Calculations and Examples

A cheetah accelerating at 6.0 m/s² can speed up from 10.5 m/s to 12.2 m/s in approximately 0.28 seconds.
A car traveling at an average speed of 55.0 mi/h over 4.25 hours covers a distance of 234 miles.
A cyclist accelerating from 10.0 m/s at 0.500 m/s² will achieve a final speed of 14.5 m/s after 9.0 seconds.

Summary of Key Concepts

Acceleration is the rate of change of velocity, which includes speeding up, slowing down, and changing direction.
On a speed vs. time graph, constant acceleration is represented by a straight line.

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Description

Test your understanding of motion concepts with these flashcards based on Chapter 11. Explore fundamental principles such as velocity, altitude, and SI units. Great for reviewing essential physics topics before an exam.