physics circular motion

What is the best overall strategy for circular-motion problems?

Find the center, draw the real forces, and determine which forces contribute to the inward net force.

What direction does centripetal acceleration point?

always towards the center of the circular path

what is the formula for centripetal acceleration?

what is the equation for net inward force in circular motion?

Is centripetal force a separate force?

no, centripetal force is the net force pointing toward the center

should i draw centripetal force on a FBD

NO. only draw real forces like gravity, normal force, tension, friction, etc.

What should you do first in a circular motion problem?

Identify where the center of the circular path is

Why can an object accelerate even if its speed is constant?

Its direction changes, so velocity changes.

In uniform circular motion, is velocity constant?

No. Speed is constant, but velocity changes direction

What direction does velocity point during circular motion?

Tangent to the circular path

What does tangential speed mean?

The speed of the object as it moves along the circular path

How are tangential velocity and centripetal acceleration oriented?

velocity is tangent to the circle, centripetal acceleration points inward

What happens to centripetal acceleration if speed increases while radius stays constant?

it increases because circular acceleration = v²/r

What happens to centripetal acceleration if speed doubles?

It becomes 4 times as large

What happens to centripetal acceleration if radius increases while speed stays constant?

it decreases

Does a=v²/r mean velocity and radius are always inversely related?

No. You can only describe a relationship when the other relevant quantities are held constant.

On a flat circular road, what force can provide the inward force?

static friction

Which direction does static friction point on a flat circular turn?

towards the center of the circle

is static friction always equal to µ_s * F_N?

No. static friction is <= mu s * normal Force

When does ∫_s= µ_s * F_N?

When static friction has reached its max value, “when it just starts to slip, etc”

On a flat surface with no vertical acceleration, what is the relationship between normal force and gravity?

normal force = gravity

Why would an object slide on a flat turn if there were no friction?

There would be no inward force to make it follow the circular path

How can a frictionless banked road make an object turn?

The normal force is tilted, so part of it points toward the center

What forces act on an object on a frictionless banked turn?

gravity and the normal force

what provides the inner force on a frictionless banked turn?

the inward component of the normal force

why is normal force greater than gravity on a frictionless banked turn?

only the vertical component of normal force balances mg, so the full normal force is larger

What does weight mean in AP physics 1

the gravitational force on an object: W = force of g = mg

is weight always equal to normal force?

no. weight is always mg, while normal force can be larger, smaller, or equal to mg.

At the top of a vertical circle, which direction is inward

downward

at the bottom of a vertical circle, which direction is inward

upward

At the top of a vertical circle, which direction do gravity and tension point

both point downward, toward the center

At the bottom of a vertical circle, which direction do gravity and tension point?

Tension points upward toward the center, while gravity points downward.

If a string breaks while an object is moving in a circle, what direction does the object move?

Tangent to the circle at the instant the string breaks.

After a string breaks, does the object continue in circular motion?

No. The force causing the circular motion is gone.

What type of motion often happens after a string breaks?

Projectile motion

At the top of a vertical circle, what direction is the object’s velocity?

Horizontal and tangent to the circle.

Why does a faster rotating object on a string tilt farther outward?

A faster speed requires a larger inward force, so tension needs a larger inward component.

Why is the string nearly vertical when tangential speed is very small?

Very little inward force is needed, so tension needs only a small horizontal component.

How do you usually turn an experimental equation into a straight-line graph?

Rewrite it in the form y=mx+b