Motion in a circle

Question 1

What is angular displacement?

Question 2

What is angular velocity?

Question 3

What is centripetal accleration?

Question 4

What is centripetal force?

Question 5

What is Radian?

Question 6

What is Period?

Question 7

What is Frequency?

Question 8

What is meant by the period of a body in circular motion?

Answer 8

The time taken for one full rotation

Question 9

What kind of force is required to keep an object moving in a circle at constant speed?

Answer 9

• A constant centripetal force
• This force always acts towards the centre of the circular path

Question 10

True or False?
The centripetal acceleration and the velocity of a body moving in a circle are always in the same direction

Answer 10

• False
• The velocity always follows the tangent to the circle.
• The centripetal force and hence the acceleration act along its radius (towards the centre).
• They are always perpendicular

Question 11

How are linear and angular velocity related?

Answer 11

• v = rw / υ/ω= r
• where:
• ‘v’ is the linear velocity
• ‘w’ is the angular velocity
• ‘r’ is the radius of the circle

Question 12

How are angular velocity and the oscillation period related?

Answer 12

• w = 2π/T
• where:
• ‘w’ is the angular velocity
• ‘T’ is the period

Question 13

True or False?
A body moving in a circle at a constant speed is not accelerating.

Answer 13

• False
• The direction is always changing
• hence the absolute velocity is always changing (even is the angular velocity remains constant)
• this means the body is accelerating

Question 14

What equation gives acceleration in terms of velocity?

Answer 14

• a = rw^2

Question 15

What is acceleration in terms of linear velocity?

Answer 15

• a = v^2 / r

Question 16

What are the equations for centripetal force?

Answer 16

• F = mv^2/r
• F = mrw^2