Circular Motion And Oscillations

Question 0

Define one radian

Answer 0

The angle subtended at the centre of a circle by an arc of length equal to the circles radius

Question 1

Newton’s law of gravitation

Answer 1

The gravitational force of attraction between two bodies is directly proportional to the product of their masses, and inversely proportional to the square of the distance between them

Question 2

Define the period T of an object in circular motion

Answer 2

The time taken to complete one revolution.

It is related to the speed v, and the radius r by the equation:

vT = 2 x pi x r

Question 3

Equation for centripetal force

Answer 3

F = m x v^2
—–
r

Question 4

What is a field?

Answer 4

The region in which a force operates

Question 5

What is the gravitational field strength at any point?

Answer 5

The force acting per unit mass at that point

Question 6

Newtons laws applied to circular motion

Answer 6

F = (m x v^2) / r

Question 7

Define angular speed

Answer 7

The angle an object rotates through per second

Question 8

Why are objects travelling in circles accelerating even if they are travelling at constant speed?

Answer 8

Even if the object is going at constant speed, it’s velocity is changing since its direction is changing

Since acceleration is defined as the rate of change of velocity, the object is accelerating even though it isn’t going any faster

Question 9

Define a period

Answer 9

The period (T) of an object in a circular motion is the time taken to complete one revolution

Question 10

Speed of an object travelling in a circle?

Answer 10

Distance / time = circumference of circle / period

V = (2 x pi x r) / T

Question 11

How do you work out centripetal acceleration?

Answer 11

With a constant speed v,

a = v^2 / r

In a direction towards the centre of the circle

Question 12

Define angular momentum

Answer 12

A property of an object that depends on its angular velocity

Question 13

Define amplitude, waves (X0)

Answer 13

The maximum displacement of a wave from its mean (or rest) position measured in metres

Question 14

Define geostationary object

Answer 14

The orbit of an artificial satellite which has a period equal to one day, so that the satellite remains above the same point on the Earth’s equator

From Earth the satellite appears to be stationary

Question 15

Equations for orbital speed

Answer 15

v = (2 x pi x r) / T

g = v^2 / r

Question 16

What is an astronomical unit?

Answer 16

The average distance of the Earth from the Sun

Question 17

Define amplitude, oscillations (X0)

Answer 17

The maximum displacement from the rest or equilibrium position, measured in metres

Question 18

What is Kepler’s third law of planetary motion?

Answer 18

The square of the period T of a planet is proportional to the cube of its distance r from the Sun

Question 19

Define gravitational field strength

Answer 19

The GFS at a point is the gravitational force exerted per unit mass on an object at that point

Question 20

Frequency

Answer 20

The number of oscillations per unit time. unit: Hz

Question 21

Phase difference

Answer 21

The fraction of an oscillation between the vibration of two oscillating particles

Question 22

Define amplitude

Answer 22

The maximum displacement of a particle from its equilibrium position

Question 23

Define angular displacement

Answer 23

The angle through which an object moves in a circle

Question 24

Define natural frequency

Answer 24

The unforced frequency of a freely oscillating object

Question 25

Define resonance

Answer 25

The forced motion of an oscillator. Max amplitude is achieved when the forcing frequency matches the oscillators natural frequency

Question 26

Define simple harmonic motion

Answer 26

Motion of an oscillator where its acceleration is directly proportional to its displacement from equilibrium position and acceleration is directed towards the equilibrium position

Question 27

Define centripetal force

Answer 27

The net force acting on an object moving in a circle; always directed towards the centre

Question 28

Define damping

Answer 28

An oscillatory motion where amplitude decreases with time due to energy losses

Question 29

What is meant by centripetal acceleration?

Answer 29

The acceleration of a body moving in a circle with constant speed acting towards the centre of the circle

Question 30

What is meant by centripetal force?

Answer 30

The resultant force on an object, acting towards the centre of the circle, causing it to move in a circular path

Question 31

Define displacement (x)

Answer 31

The distance an object moves from its rest position

May be positive or negative

Question 32

Define amplitude

Answer 32

The maximum displacement

Always positive

Question 33

Define frequency

Answer 33

The number of oscillations per unit time at any point

Question 34

Define period

Answer 34

The mean time for one complete pattern of oscillations to take place at any point

Question 35

Define phase difference

Answer 35

The angle in radians between two oscillations

Question 36

Define S.H.M

Answer 36

When the acceleration (a) of an object is proportional to its displacement (x), and the acceleration is in the opposite direction to the displacement

a ∝ -x

Question 37

The period of an object with simple harmonic motion is ____________ of its amplitude

Answer 37

Independent

Question 38

For S.H.M. the acceleration of the mass is at a _________ at the midpoint of the oscillations

Answer 38

Minimum

Question 39

For S.H.M. the acceleration of the mass is ___________ proportional to the displacement

Answer 39

Inversely