Flashcards: Motion and Equations of Motion — 54 cards

What is the state called when an object does not change position relative to surroundings?

Rest

What is the state called when an object changes position relative to surroundings?

Motion

What describes motion of an object relative to another object or observer?

Relative motion

How is a passenger in a moving train at rest relative to others?

They do not change position relative to other passengers

How is a passenger in a moving train in motion relative to a person outside?

They change position relative to the person standing outside

What defines translatory motion in an object?

Every point moves the same distance in a given time.

What path does an object follow in linear motion?

A straight path.

What path characterizes circular motion?

A circular path.

Give an example of circular motion.

Earth's motion around the Sun.

What is random motion?

Motion with no definite shape or pattern.

What does rotatory motion involve?

An object rotating about its own axis.

What is an example of rotatory motion?

A fan spinning.

What is vibratory motion?

To-and-fro motion about a mean position.

What is distance in physics?

The total length between two points or path covered without direction.

Is distance a scalar or vector quantity?

Distance is a scalar quantity.

In which units is distance measured in the SI system?

Distance is measured in metres.

What is displacement in physics?

The shortest directed distance between initial and final positions.

Is displacement a scalar or vector quantity?

Displacement is a vector quantity.

What values can displacement have?

Displacement can be positive, negative, or zero.

In which units is displacement measured in the SI system?

Displacement is measured in metres.

What is the displacement if an object moves 3 km east then 4 km west?

1 km west from the initial position.

What is speed in terms of distance and time?

Speed is the rate of change of distance per unit time.

What formula calculates speed?

Speed is calculated by $v = \frac{s}{t}$.

What is the SI unit of speed?

The SI unit of speed is meters per second (m/s).

What defines velocity in terms of displacement and time?

Velocity is the rate of change of displacement per unit time in a particular direction.

What formula calculates velocity?

Velocity is calculated by $\vec{v} = \frac{\Delta \vec{s}}{\Delta t}$.

What is the SI unit of velocity?

The SI unit of velocity is meters per second (m/s).

What does uniform speed mean?

Uniform speed means covering equal distances in equal time intervals.

How does uniform velocity differ from uniform speed?

Uniform velocity means covering equal displacements in equal time intervals.

What is acceleration in physics?

The rate of change of velocity with respect to time.

What is the formula for acceleration using velocity change and time?

$\vec{a} = \frac{\Delta \vec{v}}{\Delta t} = \frac{\vec{v}_f - \vec{v}_i}{t_2-t_1}$

What is the acceleration if velocity changes from 10 m/s to 20 m/s in 5 seconds?

2 m/s²

What defines a scalar quantity?

It has magnitude and a unit but no direction.

Name one example of a scalar quantity.

Distance

What defines a vector quantity?

It has magnitude, a unit, and direction.

Name one example of a vector quantity.

Force

When do Newton's equations of motion apply?

When acceleration is uniform.

What is the first equation of motion?

$v_f = v_i + at$

How is acceleration defined in uniform motion?

$a = \frac{\Delta v}{\Delta t}$

What is the second equation of motion?

$s = v_i t + \frac{1}{2}at^2$

What is the third equation of motion?

$v_f^2 = v_i^2 + 2as$

How is the third equation of motion derived?

By squaring the first equation, expanding with $(a+b)^2 = a^2 + 2ab + b^2$, and substituting displacement.

What is acceleration due to gravity?

Acceleration produced in a body by Earth's gravity.

What defines motion under gravity?

Motion produced in a body only by Earth's gravitational force.

Why is gravity negative for an object moving upward?

Because upward motion is opposite to the gravitational force.

What is the final velocity of a body thrown upward at 50 m/s at maximum height?

Zero.

What is the maximum height reached by a body thrown upward at 50 m/s with acceleration -9.8 m/s²?

127.55 meters.

What is the initial velocity of a ball dropped from 50 m?

Zero.

What is the approximate speed of a ball hitting the ground dropped from 50 m with g = 10 m/s²?

31.62 m/s.

Who stated that heavier objects fall first?

Aristotle.

What did Aristotle say about falling speed and weight?

Falling speed is directly proportional to an object's weight.

Did Aristotle define the concept of acceleration?

No, he did not define acceleration.

What did Aristotle discuss instead of acceleration?

He discussed speed in relation to weight.

What objects illustrate the comparison of falling speeds in gravity discussion?

A feather and a stone dropped together in an air-filled glass tube.