Test 4 physics

All three are released from rest at the top on an inclined plane. The three objects proceed down the incline undergoing rolling motion without slipping. In which order do the object reach the bottom of the incline?

1) A solid sphere 2) a solid disk 3) a hoop

A spinning skater draws in her outstretched arms thereby reducing her moment of inertia by a factor of 2. Determind the ratio of her final kinetic energy to her initial kinetic energy.

2

a cable stretches by an amount d as it supports a crate of mass M the cable is cut in half. What is the mass of the load that can be supported by either half of the cable if the cable stretches by an amount d?

2M

A cable stretches by an amount d when it supports a crate of mass M the cable is replaced by another cable of the same material having the same length and twice the diameter. what is the mass of the load that can be supported by the thicker cable if it stretches by an amount d?

4M

A solid sphere of radius R rotates about a diameter with an angular speed w. The sphere then collapses under the action of internal forces to a final radius R/2. What is the final angular speed of the sphere?

4w

A vertical block-spring system on earth has a period of 6.0 s. What is the period of this same system on the moon where the acceleration due to gravity is roughly 1/6 that of earth?

6 s

Incompressible fluid

A fluid in which the density of the liquid remains constant as the pressure changes

restoring force

A force which tends to restore an object to its original state. For example, the force which tends to pull a stretched spring back to its unstretched or equilibrium position.

ideal spring

A spring which behaves according to the relationship Fx^(applied)=kx and which has no internal friction

A curtain hangs straight down in front of an open window. A sudden gust of wind blows past the window; and the curtain is pulled out of the window. Which law, principle, or equation can be used to explain this movement of the curtain?

Bernoullis equation

what happens when a spinning ice skater draws in her outstretched arms?

Her moment of inertia decreases causing her to speed up

Which one of the following statements concerning the moment of inertia I is false?

I may be expressed in units of kg m 2 . ---->>(b) I depends on the angular acceleration of the object as it rotates. (c) I depends on the location of the rotation axis relative to the particles that make up the object. (d) I depends on the orientation of the rotation axis relative to the particles that make up the object. (e) Of the particles that make up an object, the particle with the smallest mass may contribute the greatest amount to I.

which one of the following statements concerning fluid streamlines is true?

In steady flow the pattern of streamlines does not change with time

SI units of the shear modulus

N/m^2

A u shaped tube is connected to a flexible tube that has a membrane covered funnel on the opposite end as shown in the drawing. Jason finds that no matter which way he orients to membrane, the height of the liquid in the u shaped tube does not change. Which of the following choices best describes this behavior?

Pascals principle

A ball of mass M moves in a circular path on a horizontal, frictionless surface. It is attached to a light string that passes through a hole in there center of the table. If the string is pulled down, thereby reducing the radius of the path of the ball, the speed of the ball is observed to increase. Complete the following sentence: This occurs because---:

The angular momentum of the ball is conserved.

A child standing on the edge of a freely spinning merry-go-round moves quickly to the center. Which one of the following statements is necessarily true concerning this event and why?

The angular speed of the system increases because the moment of inertia of the system has decreased

Mass Density

The mass of a volume of a substance divided by the volume

Two uniform solid spheres A and B have the same mass. The radius of sphere B is twice that of sphere A. The axis of rotation passes through each sphere. Which one of the following statements concerning the moments of inertia of these spheres is true?

The moment of inertia of A is one fourth that of B

A solid sphere and a hollow sphere each of mass M and radius R are released at the same time. from the top of an inclined plane. Which of the following statements are necessarily true?

The solid sphere will reach the bottom first

a spinning star begins to collapse under its own gravitational pull. Which one of the following occurs as the star becomes smaller?

The stars angular momentum remains constant

Youngs modulus cannot be applied to

a compressed liquid

viscous fluid

a fluid that does not flow readily like honey due to the viscosity of the fluid

Archimedes principle

a fluid will exert an upward buoyant force on an object wholly or partially immersed in it equal to the weight of the fluid displaced by the object

in general the term stress refers to

a force per unit area

fluid

a material which has the ability to flow. Usually fluids are liquids and gases

Ideal fluid

an incompressible non viscous fluid

which one of the following statements concerning a completely enclosed fluid is true?

any change in applied pressure produces an equal change in pressure at all points within the fluid.

Pascals principle

any change in pressure applied to a completely enclosed fluid is transmitted undiminished to all parts of the fluid and the walls of the container

Streamline flow

at any given point in the fluid, the velocity is constant in time

which one of the following terms is used to describe a system in which the degree of damping is just enough to stop the system from oscillating?

critically damped

a cable stretches by an amount d when it supports a crate of mass M. the cable is then cut in half. if the same crate is supported by either half of the cable, by how much will the cable stretch?

d/2

a cable stretches by an amount d when it supports a crate of mass M the cable is replaced by another cable of the same material having the same length and twice the diameter. If the same crate is supported by the thicker cable, by how much will the cable stretch?

d/4

In order to increase the frequency of the motion, one would have to

decrease the mass of the block on the end of the spring

Bernoulli principle is a statement of

energy conservation in dynamic fluids

which one of the following statements concerning hooke's law is false?

hooke's law is valid only for springs

which one of the following statements is true concerning the motion of the block?

its acceleration is greatest when the mass has reached its maximum displacement

streamline

lines representing the trajectory of the fluid particles in a steadily flowing fluid.

A simple pendulum consists of a ball of mass m suspended from the ceiling using a string of length L. The ball is displaced from its equilibrium position by a small angle (Theda). what is the magnitude of the restoring force that moves the ball towards its equilibrium position and produces simple harmonic motion?

mg(sintheda)

steady fluid flow

movement in which the velocity of the fluid particles at any point in the fluid is constant with time. Every particle that passes through a particular point in the fluid has the same velocity

the operation of a hydraulic jack is an application of

pascals principle

law used to determine the volume flow rate of a liquid that is forced through a hydrodermic needle?

poiseuille's law

gauge pressure

the amount by which a pressure exceeds atmospheric pressure

absolute pressure

the amount by which a pressure exceeds the pressure of a true vacuum

A hollow cylinder of mass M and radius R rolls down an inclined plane. A block of mass M slides down an identical inclined plane. complete the following statement: If both objects are released at the same time ---.

the block will reach the bottom first.

In order to calculate stress on the box, in addition to the information given, one must also know

the bulk modulus of the material from which the box is made

which one of the following statements concerning the buoyant force on an object submerged in a liquid is true?

the buoyant force depends on the volume of the liquid displaced

Resonance occurs in harmonic motion when:

the driving frequency is the same as the natural frequency of the system.

True concerning the derivation or usage of Bernoullis equation

the fluid must be non-viscous streamline flow is assumed the fluid must be incompressible the work energy theorem is used to derive bernoullis equation

strain

the fractional change in length or volume that results from an applied force

Each of the objects has mass M and radius R. The axis of rotation passes through the center of each object, and is perpendicular to the plane of the hoop and the plane of the flat disk. Which object requires the largest torque to give it the same angular acceleration?

the hoop

The two dams are identical with the exception that the water reservoir behind dam A extends twice the horizontal distance behind it as that of dam B. Which one of the following statements regarding these dams is correct?

the horizontal distance of the water behind the two dams does not determine the force on them.

stress

the magnitude of the force per unit area required to cause an elastic deformation

specify gravity

the mass density of the material compared to the mass density of water at 4 degrees Celsius

equation of continuity

the mass of fluid that enters one end of a pipe must leave at the other end. In other words. the mass flow rate must remain constant between any two positions along a tube of flowing fluid.

mass flow rate

the mass of fluid which flows past a given point per unit time units are kg/s

amplitude

the maximum distance that an oscillating object moves away from its equilibrium position

buoyant force

the net force exerted by a fluid on an object which is partially or wholly immersed in the fluid. the direction go the buoyant force is up

frequency

the number of cycles of oscillatory motion that occurs in one second.

Which one of the following statements is true concerning an object executing simple harmonic motion?

the object's velocity is zero when its acceleration is a maximum

simple harmonic motion

the oscillatory motion that results when an elastic material is subjected to the restoring force of an ideal spring.

Pressure on a surface

the perpendicular component of the force acting on the surface divided by the area of the surface

Youngs modulus

the proportionality constant which relates the fractional change in length of a material to the force per unit area applied to the material

bulk modulus

the proportionality constant which relates the fractional change in volume of a material to the pressure applied to the material

shear modulus

the proportionality constant which relates the shear deformation per unit length of a material to the force per unit area applied to the material

Hooke's law

the relationship which states that stress is directly proportional to strain

elasticity

the tendency for a solid object to return to its original shape after it has been stretched compressed or otherwise distorted by outside forces

period

the time required to complete one oscillatory cycle of motion

A solid cylinder with a mass m and radius r is mounted so that it can be rotated about an axis that passes through the center of both ends. At what angular speed w must the cylinder rotate to have the same total kinetic energy that it would have if it were moving horizontally with a speed v without rotation?

w=v/r(sqrt(2))