2.2 Centripetal Forces

Question 1

When turning a corner at a steady speed what direction is the force acting on us?

Answer 1

Towards the centre of the circle of turn

Question 2

What is this force a result of?

Answer 2

Newton’s 1st Law, as we want to continue straight

Question 3

What is the name of this force?

Answer 3

Centripetal force

Question 4

Name of something pointing away from the centre of the circle?

Answer 4

Centrifugal

Question 5

What would we feel without centripetal force during a turn?

Answer 5

thrown away from the centre of the curve of travel

Question 6

When travelling in a circle does the direction change?

Answer 6

Yes constantly.

Question 7

Is the velocity changed?

Answer 7

Yes, as the object will keep accelerating at a tangent to centripetal force this happens due to constantly changing direction

Question 8

Is the speed changed?

Answer 8

No, unless accelerated

Question 9

What is the centripetal force a result of?What law

Answer 9

Newton’s second law

Question 10

What else is perpendicular to tangential velocity/acceleration

Answer 10

Centripetal acceleration

Question 11

What is centripetal force when looking at the reaction force?

Answer 11

The horizontal component of the reaction force

Question 12

What is the centripetal force?

Answer 12

a force acting on a moving body at angle to direction of motion, tending to make the body followed a curved path

Question 13

equation for centripetal acceleration?

Answer 13

a = v^2/r or a = rω^2 
where 
a  = centripetal acceleration 
v = linear velocity 
ω = angular velocity 
r = radius

Question 14

What does centripetal force keep doing?

Answer 14

Keeping object moving in a circle due to newton’s second law, it causes centripetal acceleration towards the centre of the rotation

Question 15

How can we investigate centripetal force?

Answer 15

A glass tubing with a string passing through it. The string has a rubber bang on one end and some hanging masses on the other. A person is made to swing the string with the rubber bang by holding the glass tubing, but the hanging masses have to stay stationary.

Question 16

How does this practical work?

Answer 16

We find the period by counting oscillations in a certain time. With assumptions of:
- there is no friction between glass and string (can be done by smoothening the glass using heat)
- string in exactly horizontal to whirling rubber bang
we can assume Mg = mrω^2

Question 17

equation for centripetal force?

Answer 17

f = mrω^2 or f = mv^2/r 
where 
f = centripetal force 
m = mass 
r = radius 
ω = angular velocity

Question 18

What would happen if centripetal force wasn’t present?

Answer 18

The body would fly off at the tangent of velocity at that point in time

Question 19

Examples of circular motion in real life

Answer 19

• water skiers
• cyclists on velodrome tracks
• single sock in a spin drying machine
• moon circling the earth
• gymnast on a high bar