Physics Exam 2 Quizzes

Is the normal force affected by any other forces? Only when there is no friction. No, it is only due to the surface. Yes, it is changed by forces that are perpendicular to the normal force Yes, it is changed by forces that are parallel to the normal force.

Yes, it is changed by forces that are parallel to the normal force.

An object is connected to a string which goes over a pulley which has mass and a radius R. How is the acceleration of the object, a, related to the rotation of the pulley? a = α/R There is no relation. a = R/α a = αR

a = αR

Which is true for a rotating object? acp = α always α>acp always acp>0 even when α=0 α>0 even when acp=0

acp>0 even when α=0

The symbol used for a frictional force is

f

An object is connected to a string which goes over a pulley which has mass and a radius R. How is the speed of the object, v, related to the rotation of the pulley? There is no relation. v = ωR v = R/ω v = ω/R

v = ωR

How are the mass (m) and weight (w) of an object related? m = wg They are the same thing w = m/g w = mg

w = mg

How are angular acceleration, α, and torque, τ, related for a single particle with mass m? α = τ/(mr2) α = rFm α = τ/m α = τmr2

α = τ/(mr^2)

Tangential acceleration is equal to α acp α*r α/acp

α*r

Newton's 2nd law for rotation says αis proportional to F+τ Mass τnet Fnet

τnet

A car is moving at 10 m/s. What is the speed of the point on the tire which is in contact with the road? 0 m/s 5 m/s 10 m/s 20 m/s

0 m/s

Newton's Law of Gravity says the gravitational force between two objects is related to the distance, r, between them as r2 r 1/r 1/r2

1/r2

When analyzing an interaction involving three interacting objects how many free body diagrams need to be drawn? 3 - one for each object The number of diagrams depends on how the objects are arranged. 0 - can't draw free body diagrams for interacting objects 1 - all objects together

3 - one for each object

How can the apparent weight of on object be measured? Only with special equipment A simple scale Apparent weight is not real and can't be measured There is no known way to measure apparent weight.

A simple scale

Two planets have the same mass, but planet X has twice the radius of planet Z. How does the acceleration due to gravity compare between the two? Acceleration due to gravity is larger on X Acceleration due to gravity is larger on Z Acceleration due to gravity is the same on both This is not in this chapter.

Acceleration due to gravity is larger on Z

How are acceleration and force related? Acceleration is equal to force Acceleration is inversely proportional to force Acceleration has no relation to force Acceleration is directly proportional to force

Acceleration is directly proportional to force

A car rounding a corner at a constant speed has Acceleration directed forward Acceleration directed backward Acceleration toward the center of the curve Zero acceleration

Acceleration toward the center of the curve

Newton's 3rd law says All forces occur as a part of an action/reaction pair The force each object in a reaction pair experiences depends on the mass of the object 2 forces on 2 different objects cancel The net force on any object is zero.

All forces occur as a part of an action/reaction pair

The critical speed for traveling around a vertical loop Is the slowest possible speed that can still complete the loop Is the speed at which the normal force is zero at the top Depends on the radius of the loop All of the above

All of the above

When is your weight different than your apparent weight? When an elevator starts moving up When an elevator comes to a stop When an elevator starts moving down None of these All of the above

All of the above

A free body diagram should include A coordinate system The object represented as a dot All forces represented as vectors All of these

All of these

Drag on an object moving through a fluid depends on Inertial force of the fluid Speed of the object All of these Viscous force of the fluid

All of these

The moment of inertia of an extended object depends on All of these Mass of the object The shape of the object Location of the rotation axis

All of these

Torque depends on Angle of the force All of these. Magnitude of the force applied Distance, r, of applied force from pivot point

All of these

What approximations are made when dealing with pulleys and ropes in chapter 5? All of these There are no simplifications The pulley is frictionless The pulley is massless The string is massless

All of these

Which of these is in free fall around the Earth? A GPS satellite The moon All of these The international space station

All of these

Which of these is a part of the definition of a force? A push or a pull Acts on an object Requires an agent to create the force All of these are correct

All of these are correct

Rolling motion Depends on a momentarily stationary pivot point All of these are true Is a combination of linear and rotational motion Has a different speed for each point on the object

All of these are true

Which of these is not a unit of force? Newton Pound (kg m)/sec2 All of these are units of force

All of these are units of force

Newton's first law says

An object's velocity will be constant (both speed and direction) as long as no force acts on it.

Every point on a rotating rigid body has the same Linear velocity Acceleration Angular velocity Radial position

Angular velocity

In order for a bicycle wheel to roll on the street the bottom of the wheel must Experience a larger normal force Experience no friction Experience kinetic friction Be stationary

Be stationary

At what point on a roller coaster loop is your apparent weight the greatest Half way up while moving up Top Half way up while moving down Bottom

Bottom

The center of gravity of an extended object Is not in this chapter Can be calculated from the center of gravity of individual pieces of the object Is the center of gravity of the largest piece Is the center of gravity of the smallest piece

Can be calculated from the center of gravity of individual pieces of the object

How does a massless, frictionless pulley change the tension in a string? The pulley changes nothing. Changes the direction and magnitude of the tension Changes the direction of the tension Changes the magnitude of the tension

Changes the direction of the tension

An object moving in uniform circular motion has Increasing frequency Constant non-zero angular acceleration Constant angular velocity Constant angular position

Constant angular velocity

Angular velocity is positive for clockwise rotation depends on the situation angular velocity has no sign counterclockwise rotation

Counterclockwise rotation

If the center of gravity of an object is below its pivot point, the object will Experience no torque Experience counterclockwise torque due to gravity Experience clockwise torque due to gravity Rotate continuously

Experience no torque

What is the force, F, needed to keep an object with mass m in a circular path with radius r at a speed v? F = mv2/r F = r/mv F = mrv2 F = v2/mr

F = mv2/r

When trying to slide an object on a rough surface, what requires a larger force? There is no general trend. Getting it started It is the same force for starting it and continuing its motion Keeping it going

Getting it started

What has the larger moment of inertia, a cylindrical disk or a cylindrical hoop? They have the same mass and radius. Depends on what they are made of They have the same moment of inertia Disk Hoop

Hoop

What is the rotational analog to mass? α I τ F*m

I

The net force on an object is In the same direction as the acceleration Is in the opposite direction as the acceleration Not related to the acceleration Perpendicular to the acceleration

In the same direction as the acceleration

How does including the mass and radius of a pulley change the time for a bucket attached to a string going around a pulley to fall? Depends on the mass of the pulley Fall time is constant Decreases the time for the bucket to fall. Increases the time for the bucket to fall

Increases the time for the bucket to fall

The tendency of an object to resist a change in its motion is known as

Inertia

The acceleration of an object has what kind of relation to the mass of the object?

Inverse

An object in orbit around the Earth Has no forces acting on it Must have a force pushing it forward Is in free fall Must be very far from the Earth (outside the moon's orbit)

Is in free fall

The centrifugal force Is not a real force Keeps planets in orbit around a star Pulls on object into a turn Pushes objects out of a turn

Is not a real force

An object near the Earth is weightless if The net force on it is zero There are no forces on it It is in free fall It is too light to be weighed

It is in free fall

The acceleration of an object has what kind of relation to the force applied?

Linear

Which situation creates the largest torque for the same amount of force Short r with force parallel to radial line Short r with force perpendicular to radial line Long r with force parallel to radial line If force is the same torque is the same Long r with force perpendicular to radial line

Long r with force perpendicular to radial line

A satellite is in a circular orbit around the Earth. What mass(es) does the orbital speed depend on? Mass of the Earth only The speed does not depend on mass. Mass of the Earth and the satellite Mass of the satellite only

Mass of the Earth only

An object in dynamic equilibrium is Moving with a constant velocity Moving with a constant acceleration Moving with a constant speed but changing direction Stationary

Moving with a constant velocity

Is the net force larger when an object is in static equilibrium or dynamic equilibrium Depends on the mass of the object Dynamic equilibrium Static equilibrium Net force for both is zero.

Net force for both is zero.

What can be said about the net force on an object when its velocity is changing? Net force is zero The net force is perpendicular to the acceleration. Net force is in the same direction as the acceleration. The net force must be changing as well.

Net force is in the same direction as the acceleration.

The frictional force is

Parallel to the surface the object is on

The time for an object to complete one revolution is caller Frequency Period rpm Angular velocity

Period

The normal force is always Less than the weight Perpendicular to the weight Equal to the weight Perpendicular to the surface

Perpendicular to the surface

The unit for angular position used in this chapter is Degrees Arc sec Meters/second Radians

Radians

Which of these does the kinetic frictional force not depend on? Material of the object Speed of the motion Normal force on the object Material of the surface

Speed of the motion

How does the coefficient of static friction usually compare to the coefficient of kinetic friction? Static = kinetic Static < kinetic Static > kinetic No relation between the two.

Static > kinetic

The acceleration in the x-direction is determined by the Sum of the x-components of all forces acting on the object Sum of forces that are only in the x-direction acting on the object Largest force on the object Sum of x and y components of all forces on the object

Sum of the x-components of all forces acting on the object

How are period (T) and frequency (f) in circular motion related? T = 1/f T = f T = 1/f2 T = f2

T = 1/f

Which of Newton's laws are important for analyzing interacting objects? Only the 3rd law (law of force pairs) None of Newton's laws help in this situation. Only the 2nd law (law of motion) The 2nd and 3rdlaws

The 2nd and 3rdlaws

Dynamics, or the study of forces, is the study of

The causes of motion

Terminal speed occurs when The drag force is perpendicular to the acceleration The drag force is equal in magnitude to the weight The drag force is equal to the acceleration The drag force is less than the weight

The drag force is equal in magnitude to the weight

As the distance between 2 objects increases, what happens to the force of gravity between them? The force is constant The change in the force depends on the ratio of the masses. The force increases The force decreases

The force decreases

The normal force is

The force of a surface on an object perpendicular to the surface

When a cat jumps from the floor onto a table, what can be said about the force on the floor The force of the floor on the cat is less than the force of the cat on the floor The force of the floor on the cat is greater than the force of the cat on the floor The force of the floor on the cat is equal to the force of the cat on the floor There is no force on the floor. The floor doesn't move.

The force of the floor on the cat is equal to the force of the cat on the floor

The other force in the action/reaction pair of a hammer striking a nail in a wall is None of these. The force of the nail on the hammer The force of the wall on the nail The force of the nail on the wall

The force of the nail on the hammer

Your maximum walking speed is determined by The flexibility in your hips The mass of your leg The rate of arm motion The length of your leg

The length of your leg

The acceleration due to gravity near the surface of the moon depends on The mass of the moon Nothing. The acceleration due to gravity is the same everywhere. The radius of the moon The mass and radius of the moon

The mass and radius of the moon

The period of a satellite orbiting a planet does not depend on The period depends on none of these. The distance between the planet and the satellite The mass of the planet The mass of the satellite

The mass of the satellite

The speed of a satellite in a circular orbit around a star does not depend on The mass of the star The mass of the satellite The speed depends on all of these The distance between the star and the satellite

The mass of the satellite

When an object's speed is decreasing The net force and the acceleration are in the same direction of the motion The net force and the acceleration are opposite the motion The net force is opposite the motion, and the acceleration is in the direction of the motion The net force is in the direction of the motion, and the acceleration is opposite the motion

The net force and the acceleration are opposite the motion

If an object is in equilibrium, what does Newton's 2nd law tell us? The net force is in the direction of motion The net force is zero. The net force is in the opposite direction as the motion The net force is perpendicular to the motion

The net force is zero

If the speed of a moving object is not changing, then There are no forces on the object The net force is zero The net force is in the direction of the motion The net force is in the direction opposite the motion.

The net force is zero

The kinetic frictional force is proportional to The width of the object. The normal force on the object The height of the object The net force on the object

The normal force on the object

How does banking a curve on the highway allow cars to drive at a higher speed in the curve? The normal force provides some centripetal acceleration The frictional force is increased. The normal force provides some centrifugal acceleration the normal force is increased.

The normal force provides some centripetal acceleration

The feeling of weightless near the Earth means None of these There is no gravity The weight is zero The object is in free fall

The object is in free fall

The maximum safe speed to turn a corner depends on The kinetic friction between the tires and the road The static friction between the tires and the road The mass of the car The length of the car

The static friction between the tires and the road

When two objects are connected by a string how are the tension forces on each object related? The tension forces on each object are the same The relationship between the tension forces depends on the type of string. The ratio of the tension forces is equal to the ratio of the masses The ratio of the tension forces is equal to the ratio of the surface areas

The tension forces on each object are the same

The Reynolds number is used to characterize The acceleration an object experiences The type of friction between two solid surfaces The types of force exerted by gravity The types of drag an object experiences

The types of drag an object experiences

If the net force on an object is zero, what can be said about the vectors on a free body diagram The vector sum is zero All of the vectors point in the direction of the acceleration The vector sum points up There are no vectors

The vector sum is zero

The net force on an object is The sum of only the vertical forces on an object Always zero The vector sum of all the forces on the object The scalar sum of all the forces on the object

The vector sum of all the forces on the object

The y component of an object's acceleration is determined by All forces regardless of direction The y components of all of the forces The x components of all of the forces Only gravity

The y components of all of the forces

When objects are in contact with each other and moving together what is the acceleration of each object? The ratio of the accelerations is equal to the ratio of the masses. The ratio of the accelerations is equal to the ratio of their volumes The acceleration depends on the area of contact. They have the same acceleration

They have the same acceleration

An example of a long-range force is Weight Friction Tension Normal

Weight

The gravitational force of the Earth on an object close to the surface is known as

Weight