AP Physics Unit 2 Concept Check Material

Why do raindrops fall with constant speed during the later stages of their descent?

Air resistance just balances the force of gravity

When the brakes of an automobile are applied, the road exerts the greatest retarding force:

just before the wheel start to slide

The standard 1-kg mass is attached to a compressed spring and the spring is released. If the mass initially has an acceleration of 5.6 m/s2, the force of the spring has a magnitude of:

5.6 N

A person riding a Ferris wheel is strapped into her seat by a seat belt. The wheel is spun so that the centripetal acceleration is g. Select the correct combination of forces that act on her when she is at the top. Here, Fg = force of gravity, down; Fb = seat belt force, down; and Fs = seat force, up.

Fg = mg, Fb = 0, Fs = 0

Which of the following is true, according to Newton's second law?

The acceleration of an object is proportional to the net force on it and inversely proportional to its mass.

Two blocks are connected by a massless string that passes over a massless pulley, as shown. In the absence of friction, how does the tension force exerted by the string on the 250 N block compare with the tension force exerted by the string on the 350 N block?

The two forces are equal.

In SI units a force is numerically equal to the ______, when the force is applied to it.

acceleration of the standard kilogram

A coin is placed on a horizontal phonograph turntable. Let N be the normal force exerted by the turntable on the coin, f be the frictional force exerted by the turntable on the coin, and fs,max be the maximum force of the static friction. The speed of the turntable is increased in small steps. If the coin does not slide, then

f increases and both N and fs,max stay the same

An object moves around a circle. If the radius is doubled keeping the speed the same then the magnitude of the centripetal force must be:

half as great

The mass and weight of a body:

have the same ratio as that of any other body placed at that location

The term "mass" refers to the same physical concept as:

inertia

The coefficient of kinetic friction:

is not: in the direction of the frictional force, the ratio of force to area, in the direction of the normal force, and it cannot have units of Newtons

A ball is thrown upward into the air with a speed that is greater than terminal speed. On the way up it slows down and, after its speed equals the terminal speed but before it gets to the top of its trajectory:

it continues to slow down

If a satellite moves above the Earth's atmosphere in a circular orbit with constant speed, then:

its acceleration is toward the Earth

You stand on a spring scale on the floor of an elevator. Of the following, the scale shows the highest reading when the elevator:

moves upward with increasing speed

A circus performer of weight W is walking along a "high wire" as shown. The tension in the wire is:

much more than W

Acceleration is always in the direction:

of the net force

In uniform circular motion,

the accleration and the velocity are always perpendicular, and are continually changing direction.

A heavy ball is suspended as shown. A quick jerk on the lower string will break that string but a slow pull on the lower string will break the upper string. The first result occurs because:

the ball has inertia

The "reaction" force does not cancel the "action" force because:

they act on different bodies

A ball of mass m is thrown downward from the edge of a cliff with an initial speed that is three times the terminal speed. Initially the drag force on it is:

upward and greater than mg