# Linear Momentum & Rotational Motion Flashcards

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*Fg* = *mv2* / *r* = 7.35 * 1022 kg * (1000 m/s)2 / 3.8 * 108 m = 1.9 * 1020 N

Acceleration = angular acceleration, force = torque, momentum = angular momentum, velocity = angular velocity, mass = moment of inertia

An off-center force exerted on an object, causing it to spin

*m1* * *v1* + *m2* * *v2* = (*m1* + *m2*) * *vf*

(5 kg)(10 m/s) + (3 kg)(-4 m/s) = (5 kg + 3 kg) * *vf*

*vf* = 4.75 m/s east

Force * time = change in momentum

Change in momentum = 3000 kg * 0 m/s - 3000 kg * 20 m/s = -60,000 kg m/s

Time = 60,000 kg m/s / 8,000 N = 7.5 seconds

*m1* * *vi1* + *m2* * *vi2* = *m1* * *vf1* + *m2* * *vf2*

(500 kg)(10 m/s) + (1000 kg)(12 m/s) = (500 kg)(*vf1*) + (1000 kg)(14 m/s)

*vf1* = 6 m/s

An event in which two objects collide, resulting in permanent deformation or being stuck together and loss of heat

An event in which two objects collide, resulting in no permanent deformation or loss of heat

An environment containing two or more objects in which the total amount of energy does not change

No external net forces

A conserved quantity that measures a mass in motion

Can only be changed by a force external to a system

Momentum = mass * velocity = 3,000 kg * 10 m/s = 30,000 kg m/s

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## Flashcard Content Overview

In these flashcards, you will first review momentum. This includes what momentum is, how to calculate it, two different types of collisions, and the conservation of momentum. Second, you will review the relationship between translational and rotational motion and see how many equations you already know for objects moving in a linear direction can be slightly changed to solve problems involving objects moving in a circle.

Momentum = mass * velocity = 3,000 kg * 10 m/s = 30,000 kg m/s

A conserved quantity that measures a mass in motion

Can only be changed by a force external to a system

An environment containing two or more objects in which the total amount of energy does not change

No external net forces

An event in which two objects collide, resulting in no permanent deformation or loss of heat

An event in which two objects collide, resulting in permanent deformation or being stuck together and loss of heat

*m1* * *vi1* + *m2* * *vi2* = *m1* * *vf1* + *m2* * *vf2*

(500 kg)(10 m/s) + (1000 kg)(12 m/s) = (500 kg)(*vf1*) + (1000 kg)(14 m/s)

*vf1* = 6 m/s

Force * time = change in momentum

Change in momentum = 3000 kg * 0 m/s - 3000 kg * 20 m/s = -60,000 kg m/s

Time = 60,000 kg m/s / 8,000 N = 7.5 seconds

*m1* * *v1* + *m2* * *v2* = (*m1* + *m2*) * *vf*

(5 kg)(10 m/s) + (3 kg)(-4 m/s) = (5 kg + 3 kg) * *vf*

*vf* = 4.75 m/s east

An off-center force exerted on an object, causing it to spin

Acceleration = angular acceleration, force = torque, momentum = angular momentum, velocity = angular velocity, mass = moment of inertia

*Fg* = *mv2* / *r* = 7.35 * 1022 kg * (1000 m/s)2 / 3.8 * 108 m = 1.9 * 1020 N

A state that an object is in when, if slightly disturbed, it returns to its original position

Tilting raises the center of gravity

A state that an object is in when, if slightly disturbed, it tips over

Tilting lowers the center of gravity

*Fc* = *mv2* / *r* = 1.0 kg * (5 m/s)2 / 0.5 m = 50 N

Occurs because when an object is experiencing circular motion, the direction is always changing despite traveling at the same speed

*ac* = *v2* / *r*

A measure of how fast an object is rotating, with radians per second as the unit

Equation: angular velocity = change in angle / time

A measure of the rate of change in angular velocity, with radians per second squared as the unit

Occurs when an object's rotational speed is changing (different than centripetal acceleration)

*θ* = (*ωf* + *ωi*) * *t* / 2 = (9.4 rad/s + 6.3 rad/s) * 5 s / 2 = 39.2 radians

Torque = *Fr* = 10 kg * 9.8 m/s2 * 5 m = 490 Nm

10 rotations/2 minutes = 5 rotations/min = 0.52 rad/s

Kinetic energy = 1/2 * moment of inertia * angular velocity2 = 1/2 * 25 kg m2 * (0.52 rad/s)2 = 3.38 J

1/2 turn = 3.14 radians

Work = torque * rotation = 200 N * 0.15 m * 3.14 radians = 94.2 J

1/2 turn = 3.14 radians

Power = work/time But work = [torque x θ (change in angle)]

Power = [torque x θ] / time.

And, θ / time = angular velocity

So, Power = torque x angular velocity

188.4 Watts = [200 N x 0.15 m x 3.14 radians] x angular velocity

2 radians /s = angular velocity

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Physics 101: Intro to Physics20 chapters | 167 lessons | 11 flashcard sets

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