Define centripetal force .

Centripetal force is the resultant force towards the centre of a circle required to keep a body in uniform circular motion.

Give three examples of a centripetal force and the force that provides it.

A car travelling around a roundabout — friction A ball attached to a rope moving in a circle — tension The Earth orbiting the Sun — gravitational attraction

In what direction do centripetal force and centripetal acceleration act, relative to an object's linear velocity?

Both act towards the centre of the circle, perpendicular to the object's linear (tangential) velocity.

An object moves in uniform circular motion at a constant angular speed. Explain why it is still accelerating.

Because velocity is a vector. Even though the object's speed (magnitude) stays constant, its direction is constantly changing, so its velocity is constantly changing.

Angular speed does not change with radius, but .......... speed does.

Angular speed does not change with radius, but linear speed does.

True or False? Angular velocity is constant for an object in uniform circular motion.

False. Angular speed (magnitude) is constant, but angular velocity (which includes direction) is constantly changing.

Define centripetal acceleration .

Centripetal acceleration is the acceleration of an object towards the centre of a circle when the object moves around the circle at a constant speed.

Centripetal acceleration is always directed .......... the centre of the circle.

Centripetal acceleration is always directed towards the centre of the circle.

True or False? Centripetal acceleration acts in the same direction as an object's linear velocity.

False. Centripetal acceleration is always perpendicular to the object's velocity, directed towards the centre of the circle.

What are the SI units of centripetal acceleration?

Metres per second squared (m s -2 ).

Centripetal force is always directed .......... to the direction of travel.

Centripetal force is always directed perpendicular to the direction of travel.

A LevelPhysicsCambridge (CIE)Flashcards12. Motion in a CircleCentripetal Acceleration

Centripetal Acceleration (Cambridge (CIE) A Level Physics): Flashcards

Exam code: 9702

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FrontCentripetal Acceleration
Define centripetal force.
FrontCentripetal Acceleration
Give three examples of a centripetal force and the force that provides it.
BackCentripetal Acceleration
A car travelling around a roundabout — friction
A ball attached to a rope moving in a circle — tension
The Earth orbiting the Sun — gravitational attraction

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Cards in this collection (17)

Define centripetal force.
Centripetal force is the resultant force towards the centre of a circle required to keep a body in uniform circular motion.
Give three examples of a centripetal force and the force that provides it.
- A car travelling around a roundabout — friction
- A ball attached to a rope moving in a circle — tension
- The Earth orbiting the Sun — gravitational attraction
In what direction do centripetal force and centripetal acceleration act, relative to an object's linear velocity?
Both act towards the centre of the circle, perpendicular to the object's linear (tangential) velocity.
An object moves in uniform circular motion at a constant angular speed. Explain why it is still accelerating.
Because velocity is a vector. Even though the object's speed (magnitude) stays constant, its direction is constantly changing, so its velocity is constantly changing.
Angular speed does not change with radius, but .......... speed does.
Angular speed does not change with radius, but linear speed does.
True or False?
Angular velocity is constant for an object in uniform circular motion.
False.
Angular speed (magnitude) is constant, but angular velocity (which includes direction) is constantly changing.
Define centripetal acceleration.
Centripetal acceleration is the acceleration of an object towards the centre of a circle when the object moves around the circle at a constant speed.
What is the equation for centripetal acceleration in terms of linear speed (v) and radius (r)?
$a = \frac{v^{2}}{r}$
What is the equation for centripetal acceleration in terms of angular speed (ω) and radius (r)?
$a = r ω^{2}$
Centripetal acceleration is always directed .......... the centre of the circle.
Centripetal acceleration is always directed towards the centre of the circle.
True or False?
Centripetal acceleration acts in the same direction as an object's linear velocity.
False.
Centripetal acceleration is always perpendicular to the object's velocity, directed towards the centre of the circle.
What are the SI units of centripetal acceleration?
Metres per second squared (m s^-2).
What is the equation for centripetal force in terms of mass (m), velocity (v) and radius (r)?
$F = \frac{m v^{2}}{r}$
What is the equation for centripetal force in terms of mass (m), radius (r) and angular velocity (ω)?
$F = m r ω^{2}$
Centripetal force is always directed .......... to the direction of travel.
Centripetal force is always directed perpendicular to the direction of travel.
At the top of a vertical circular path, what condition determines the minimum speed needed for an object to maintain circular motion (e.g. water staying in a bucket)?
The object's weight provides exactly the centripetal force needed, so $m g = \frac{m v^{2}}{r}$ , giving a minimum speed of $v = \sqrt{g r}$
True or False?
Doubling the radius of a circular path, while keeping mass and speed constant, doubles the centripetal force required.
False.
Since $F = \frac{m v^{2}}{r}$ , force is inversely proportional to radius, so doubling the radius halves the required centripetal force.

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