Physics Final Flashcards
The preferred positive direction for angular displacement is the clockwise direction.
False
When a rigid body rotates about a fixed axis all the points in the body have the same angular displacement.
True
When a rigid body rotates about a fixed axis all the points in the body have the same angular speed.
True
When a rigid body rotates about a fixed axis all the points in the body have the same linear displacement.
False
When a rigid body rotates about a fixed axis all the points in the body have the same tangential speed.
False
When a rigid body rotates about a fixed axis all the points in the body have the same angular acceleration.
True
When a rigid body rotates about a fixed axis all the points in the body have the same tangential acceleration.
False
What is the quantity used to measure an object’s resistance to changes in rotational motion?
moment of inertia
A solid sphere, solid cylinder, and a hollow pipe all have equal masses and radi. If the three are released simultaneously at the top of an inclined plane, which will reach the bottom first?
sphere
Two children ride on a merry-go-round, George is at a greater distance from the axis of rotation than Jacques. It is a true statement that
Jacques and George have the same angular velocity.
Two children are riding on a merry-go-round. Child A is at a greater distance from the axis of rotation than child B. Which child has the larger linear displacement?
Child A
Two children are riding on a merry-go-round. Child A is at a greater distance from the axis of rotation than child B. Which child has the larger angular displacement?
They have the same non-zero angular displacement.
Two equal forces are applied to a door. The first force is applied at the midpoint of the door; the second force is applied at the doorknob. Both forces are applied perpendicular to the door. Which force exerts the greater torque?
the second at the doorknob
A person sits on a freely spinning lab stool (no friction). When this person extends her arms,
her moment of inertia increases and her angular velocity decreases.
An ice skater doing a spin pulls in her arms, decreasing her moment of inertia by a factor of two. How does her angular speed changes?
it increases by a factor of two.
A figure skater is spinning slowly with arms outstretched. She brings her arms in close to her body and her moment of inertia decreases by 1/2. Her angular speed increases by a factor of
2
A figure skater is spinning slowly with arms outstretched. She brings her arms in close to her body and her angular speed increases dramatically. The speed increase is a demonstration of
conservation of angular momentum: her moment of inertia is decreased, and so her angular speed must increase to conserve angular momentum.
A heavy boy and a lightweight girl are balanced on a massless seesaw. If they both move forward so that they are one-half their original distance from the pivot point, what will happen to the seesaw?
Nothing, the seesaw will still be balanced.
An ice skater doing a spin pulls in her arms, decreasing her moment of inertia by a factor of two, and doubling her angular speed. Her final rotational kinetic energy
is doubled.
A merry-go-round spins freely when Janice moves quickly to the center along a radius of the merry-go-round. It is true to say that
the moment of inertia of the system decreases and the angular speed increases.
An electrically neutral atom does not have a net charge.
True
A neutron carries a negative charge.
False
A neutron is approximately twice as heavy as the electron.
False
The coulomb, which is the unit of charge, is the charge on one electron.
False
Electric charge is quantized.
True
A good conductor of electricity is a bad conductor of heat.
False
The Coulomb force between two charges can be attractive or repulsive.
True
A positive charge placed in an electric field experiences a force in the direction of the field.
True
When the distance between the two charges is doubled, the force between them is
reduced by a factor of 4.
Two charges, Q1 and Q2, are separated by a certain distance. The ratio of charge @1 to charge 2 is
1:2. The ratio of force on @1 to the force on @2 is
1:1.
The main difference between conductors and insulators is in terms of
so neutrons.
valence or conduction electrons.
Two objects, A and B, are rubbed together. As a result, object A acquires an excess negative charge while object B becomes positively charged. In comparison to their masses before the charging process, you can say that
the mass of A increased and that of B decreased.
Electrical and gravitational forces follow similar equations with one main difference:
Gravitational forces are always attractive but electrical forces can be attractive or repulsive.
When atom A loses an electron to atom B,
atom A becomes a positive ion and atom B becomes a negative ion.
The charge on the proton is the same as
The charge of an electron, but opposite sign
The number of protons in the nucleus of an electrically neutral atom is equal to
the number of electrons surrounding the nucleus.
Electric potential is a scalar quantity.
True
When a proton moves in a direction of the electric field, its potential increases but its potential energy decreases.
True
When an electron moves in a direction opposite to the electric field, its potential increases but the potential energy decreases.
True
Unlike electric potential, the electric potential energy is a vector quantity.
False
Conventional current is the flow of positive charge from higher to lower potential.
True
Electron flow is in the direction of conventional current.
False
A series circuit is a current divider and a parallel circuit is a voltage divider circuit.
False
Four unequal resistors connected in series have same current but different voltages.
True
Four equal resistors connected across a DC voltage source in either series or parallel will have equal voltage drops across each resistor.
True
Four equal resistors connected in series have same current and same voltage across each resistor
True
Which one of the following is the correct statement regarding the resistance?
The resistance of a wire is directly proportional to the length of the wire.
The length of a certain wire is kept same while its radius is doubled. What is the change in the resistance of this wire?
It is reduced by a factor of 4.
Four unequal resistors are connected in a parallel circuit. Which one of the following statements is correct about this circuit?
The total resistance is less than the smallest resistor.
Four unequal resistors are connected in a series circuit. Which one of the following statements is correct about this circuit?
The total resistance is more than the largest resistor.
Which of the following statements is correct?
The north pole of a magnet points towards the Earth’s geographic north pole.
The field near a long straight wire carrying a current is inversely proportional to the current flowing through the wire.
False
The magnetic field near a current carrying wire is directly proportional to the distance from the wire.
False
A current carrying wire placed in a magnetic field perpendicular to the wire experiences a maximum force.
True
At a given location the direction of the magnetic field is the direction that the north pole of a compass points when placed at that location.
True
Magnetic field lines can never cross one another.
True
Magnetic field lines come out of the south pole of a magnet and enter at the north pole.
False
An electron moving in the positive y direction, at right angles to a magnetic field, experiences a magnetic force in the negative x direction. What is the direction of the magnetic field?
It is in the positive z direction.
According to the law of reflection of light, the angle of incidence is
equal to the angle of reflection.
Which one of the following is the correct number for the magnification of a plane mirror?
1.0
The angle of reflection is the angle between
the reflected ray and the normal drawn at the point where this ray meets the mirror
The angle of incidence is the angle between
the incident ray and the normal drawn at the point where this ray meets the mirror.
The image formed in a plane mirror is
at the same distance behind the mirror as the object is in front of the mirror
Which of the following sets of characteristics describes the image formed by a plane mirror?
virtual and upright
