When you drop a ball from rest it accelerates downward at 9.8 m/s². If you instead throw it downward, assuming no air resistance, its acceleration immediately after leaving your hand is

A heavy rock and a light rock in free fall (zero air resistance) have the same acceleration. The heavy rock doesn’t have a greater acceleration because the

A cannonball is fired horizontally at 10 m/s from a cliff. Its speed one second after being fired is about

A model airplane flies slower when flying into the wind, and faster with wind at its back. When launched at right angles to the wind, a cross wind, its groundspeed compared with flying in still air is

A karate chop delivers a force of 3000 N to a board that breaks. The force that the board exerts on the hand during this event is

A math book and a physics book sitting on a table are tied together with a length of string. With the string taut, one book is pushed off the edge of the table. As it falls, the other book is dragged horizontally across the table

surface. With no friction, acceleration of the books is

When an increase in speed doubles the momentum of a moving body, its kinetic energy

When an increase in speed doubles the kinetic energy of a moving body, its momentum

Big brother and little sister can balance on a seesaw because of balanced

When a spinning system contracts in the absence of an external torque, its rotational speed increases and its angular momentum

Consider a ball rolling down an inclined plane. The normal force on the ball (the force perpendicular to the plane).

Consider a ball rolling in a horizontal circular path on the inside surface of a cone. The normal force on the ball (force perpendicular to the surface of the cone)

When a ball at rest hangs by a single vertical string, tension in the string is mg. If the ball is made to move in a horizontal circle so that the string describes a cone, string tension

Imagine you're standing on the surface of a shrinking planet. If it shrinks to one-tenth its original diameter with no change in mass, on the shrunken surface you'd weigh

The fact that the Moon always shows its same face to Earth is evidence that the Moon rotates about its axis about once per

Satellites in circular Earth orbit maintain a constant speed because gravitational force on them is

A simple and correct way to comprehend satellites orbiting Earth is to view them as

Earth satellites such as the International Space Station orbit at altitudes that are mainly above Earth’s

The mass of an atom comes mostly from its ____ ; and its volume from its ______.

Consider a block of wood floating on water. If you push down on the top of the block until it’s completely submerged, the buoyant force on it

An inflated balloon with a heavy rock tied to it is dropped into a deep lake. As the balloon sinks deeper and deeper, the buoyant force acting on it

A principal source of the Earth’s internal energy is

The surface of Planet Earth loses energy to outer space due mostly to

The "greenhouse gases" that contribute to global warming absorb

In a mixture of hydrogen, oxygen, and nitrogen gases at a given temperature, the molecules having the greatest average speed are those of

The electrical force of attraction between an electron and a proton is greater on the

Immediately after two separated charged particles are released from rest, both increase in speed. The particles therefore have

Compared with the current in an LED lamp, the current in the connecting wire is

As more lamps are connected in a series circuit, the current in the power source

As more lamps are connected in a parallel circuit, the current in the power source

A capacitor loses half of its remaining charge every second. If after 5 seconds its charge is q, what was its initial charge?

The magnetic force on a moving charged particle can change the particle’s

A step-up transformer in an electrical circuit can step up

The mutual induction of electric and magnetic fields can produce

All of the following are electromagnetic waves EXCEPT

You swing to and fro on a playground swing. If you stand rather than sit, the time for a to-and-fro swing is

Compared with the sound you hear from the siren of a stationary fire engine, the sound you hear when it approaches you has an increased

During the time an aircraft produces a sonic boom, the aircraft is

The phenomenon of interference occurs for

The speed of sound in air depends on

Your friend states that under all conditions, any radio wave travels faster than any sound wave. You

The phenomenon of beats results from sound

To view your full-face image in a steamy mirror, compared with the height of your face, the minimum height of the patch to wipe away is

Light reflecting from a smooth surface undergoes a change in

Which of these changes when light refracts in passing from one medium to another?

When white light enters a prism, green light is bent more than

Astrophysicists are able to identify the elements in the outer layers of a star by studying its

Any atom that emits an alpha particle or beta particle

Suppose the number of neutrons in a reactor that is starting up doubles each minute, reaching one billion neutrons in 10 minutes. When did the number of neutrons reach half a billion?

When a uranium nucleus undergoes fission, the energy released is primarily in the form of

When a fusion reaction converts a pair of hydrogen isotopes to an alpha particle and a neutron, most of the energy released is in the form of

Because there is an upper limit on the speed of particles, there is also an upper limit on

Relativistic equations for time dilation, length contraction, and relativistic momentum and energy hold true

The equation E = mc² indicates that energy

When you look at the red petals of a rose, the color light you're seeing is

When the color yellow is seen on your TV screen, the phosphors being activated on the screen are

The red glow in the neon tube of an advertising sign is a result of

Polarization is a property of

If the Sun collapsed to become a black hole, Planet Earth would