Lecture 20 - Angular Kinetics : Finding the Centre of Mass

Question 1

the weight of the body is a function of the mass of …… and ..

Answer 1

mass of each particle and the acceleration due to gravity

Question 2

the point around which all the particles are evenly distributed is

Answer 2

the point at which we can draw a single weight vector (Fw)

Question 3

what is the unit for impulse

Answer 3

N.s

Question 4

what is the unit for displacement

Answer 4

m

Question 5

what is the unit for velocity

Answer 5

m/s

Question 6

what is the unit for acceleration

Answer 6

m.s^-2

Question 7

what is the unit for force

Answer 7

N

Question 8

what is the unit for inertia

Answer 8

equivalent to mass

Question 9

what is the unit for momentum

Answer 9

kg.m.s-1

Question 10

what is the unit for angular displacement

Answer 10

rad

Question 11

what is the unit for angular velocity

Answer 11

rad/s

Question 12

what is the unit for angular acceleration

Answer 12

rad.s^-2

Question 13

what is the unit for moment of force or torque

Answer 13

N.m

Question 14

what is the unit for moment of intertia

Answer 14

kg.m^2

Question 15

what is the unit for angular momentum

Answer 15

kg.m^2.s^-1

Question 16

what is the unit for angular impulse

Answer 16

N.m.s

Question 17

the centre of gravity is the point about which ….

Answer 17

the resultant torque of all forces acting on the body is zero

Question 18

what is the quantitative method to locate centre of mass

Answer 18

rcm = sum of ri mi / sum of mi

Question 19

for an athlete to complete the frosby flop they must create …

Answer 19

rotation about the “centre of mass”

Question 20

what is the first thing we have to do in the frosby flop (what type of force and what does this create)

Answer 20

first we have to do work on our centre of mass to give it kinetic energy for the jump

we have used an off centre force which created rotation of the body with our push off

Question 21

in the air what do we do in the frosby flop

Answer 21

in the air we can redistribute our segments to manipulate the location of the CoM, to control rotation of the body, keeping the CoM as near to the bar as possible