Further Mechanics FM1-5

Question 1

What is meant by ‘centripetal acceleration’?

Answer 1

It is the acceleration towards the centre of the centre of the circular path provided by the centripetal force. Changes in direction and not magnitude, therefore it isn’t constant.

Present when an object is moving in a circle.

Question 2

What is meant by ‘centripetal force’?

Answer 2

It is the resultant force directed towards the centre of the motion. It is the force that causes circular motion.

Question 3

What does ω represent?

Answer 3

Angular speeed

Question 4

What does v represent?

Answer 4

Velocity

Question 5

What does f represent?

Answer 5

frequency or the centripetal force

Question 6

For an object in circular motion how does the angular speed change?

Answer 6

ω keeps the same

Question 7

For an object in circular motion how does the velocity change?

Answer 7

v changes as the direction is constantly changing.

Question 8

For an object in circular motion how does the force change?

Answer 8

f keeps the same into the centre of what the object is moving around, changes in the direction not magnitude sense.

Question 9

For an object in circular motion how does the acceleration change?

Answer 9

a the magnitude doesn’t change but the direction is constantly changing so the acceleration isn’t constant.

Question 10

Define the angular speed?

Answer 10

The angualr displacement moved thorough (in radians or degrees) per second.

Question 11

What equations relate to angualr speed?

Answer 11

v = 2πr/T = rω;
v = rω;
T = 1/f ;
ω = 2πf;
ω = Δθ/Δt

Question 12

How is the number of radians in an angle given?

Answer 12

θ = s/r; where s is the arc length, r is the radius and θ is the angle in radians.

Question 13

How does the velocity act in a circular motion?

Answer 13

The velocity acts tangentially.

Question 14

What are the equations relating centripetal acceleration, velocity, radius and the angular speed?

Answer 14

𝑎 = 𝑣^2/𝑟 = 𝜔^2r

Question 14

How does the force and acceleration act in a circular motion?

Answer 14

Towards the centre of motion.

Question 14

What is an example of a force that does no work?

Answer 14

Centripetal forces

Question 15

What are the equations relating centripetal force, velocity, radius and the angular speed and the mass?

Answer 15

𝐹 = 𝑚v^2/ 𝑟 = 𝑚v^2r

Question 16

When a car turns a corner, what provides the required centripetal force?

Answer 16

Friction

Question 17

What provides the centripedal force for a car travelling along a banked track?

Answer 17

The reaction force between the track and the car, allowing faster speeds.

Question 18

What is the centripetal force of an object travelling in a vertical circle?

Answer 18

The centripetal force is the difference between the upward and downward forces.

Question 19

To look at the diagrams for the forces on related diagrams check on this google docs, cover up the right and think what the left would look like then check.

Answer 19

https://docs.google.com/document/d/1giyqLUlxALVbsJ9rU4qKjqp8PnTlwJLAvvKXlJ6vsQc/edit

Question 20

When does an object feel like it experiences “apparent weightlessness”?

Answer 20

When the object is in free fall, the whole of his weight provides the centripetal force to maintain that velocity at that height about earth’s surface.

Question 21

When looking at the collection of dust particles on a spinning disc there is a more concentrated on the inner part of the vinyl disc of dust, why?

Answer 21

Closer to the centre particles need smaller centripetal force.
v is directly proportional to r, or angular speed = constant along disc.
Idea that friction, electrostatic forces are sufficient to meet the requirements of particles close to the centre but not those further away.

Question 22

What is the calculation used to find the angle at which a ball moves in?

Answer 22

distance / (2 x pi x radius)