13 Circular Motion

Question 1

What is the Time Period (T) for circular motion?

Answer 1

The time for one revolution.

Question 2

What is the frequency (f) in circular motion?

Answer 2

number of revolutions per seconds.

Question 3

What is frequency measured in in circular motion?

Answer 3

hertz (Hz)

Question 4

What is linear speed (v) in circular motion?

Answer 4

The distance travelled per second.

Question 5

What is the symbol for linear speed?

Answer 5

v

Question 6

What is the definition of a radian.

Answer 6

An angle of 1 radian results in an arc with a length equal to the radius of the circle.

Question 7

What is the formula to find an angle in radians?

Answer 7

arc length / radius of the circle

Question 8

What is 180° in radians?

Answer 8

π rad.

Question 9

What equation connects frequency and time period?

Answer 9

f= 1/ T

Question 10

What is angular displacement (θ) in circular motion?

Answer 10

the angle described by the object moving in a circle, and is measured in degrees or radians.

Question 11

What is angular speed (ω) (angular velocity)?

Answer 11

The angular displacement per second and is measured in rad s^-1.

Question 12

What is the symbol for angular speed?

Answer 12

ω

Question 13

What is the equation for average linear speed?

Answer 13

Question 14

What are the 2 equations for angular speed(ω)?

Answer 14

Question 15

What is the equation for linear speed (v)?

Answer 15

Question 16

State Newton’s 1st law.

Answer 16

A body will continue with a constant velocity (i.e. in a straight line) unless acted upon by an unbalanced (resultant) force.

Question 17

If the metal ball is clearly not moving in a straight line, what must be acting on it?

Answer 17

An unbalanced (resultant) force acting on it.

Question 18

What is an unbalanced force?

Answer 18

a resultant force.

Question 19

With a whirligig, what must happen in the string if the rubber bung is to move with a greater linear speed whilst the mass and radius remain constant?

Answer 19

It increases.

Question 20

With a whirligig, what must happen to the tension in the string if the rubber bung is to move in a circle of bigger radius whilst the mass and linear speed remain constant?

Answer 20

It decreases.

Question 21

In a whirligig, what must happen to the tension in the string if a more massive rubber bung is used whilst the linear speed and radius are kept constant?

Answer 21

It increases.

Question 22

In circular motion, when the speed is doubled, the force…

Answer 22

x4

Question 23

In circular motion, when the radius is doubled, the force…

Answer 23

halves.

Question 24

In circular motion, when the mass is doubled, the force…

Answer 24

doubles

Question 25

In circular motion, when the force is doubled, the acceleration...

Answer 25

doubles.

Question 26

What is the equation linking: Force (F), mass (m), radius (r) and speed (v)

Answer 26

Question 27

For an object to act in a curved path, what must there be?

Answer 27

A force acting on the object towards the centre of the curved path to prevent the object going off at a tangent.

Question 28

What is the definition of centripetal force?

Answer 28

Any resultant force which stops an object from moving off at a tangent from a circular path is called a centripetal force. It always acts towards the centre of the curved path.

Question 29

When an object is spun in a circle, the magnitude of the centripetal force has to be bigger if: -The objects mass gets ............ -The speed of the object gets ............ -The radius of the curvature of the path gets ............ if ω is constant.

Answer 29

When an object is spun in a circle, the magnitude of the centripetal force has to be bigger if: -The objects mass gets **bigger** -The speed of the object gets **bigger** -The radius of the curvature of the path gets **bigger** if ω is constant.