Linear Kinematics - (week 24)

Question 1

state what it is meant by the key term - ‘Force of Gravity’

Answer 1

the attraction influence (force) which accelerates objects towards the earths surface at approx. g = 9.81 m/s^2

Question 2

the calculation for weight is what ?

Answer 2

weight = mass x gravitational field strength

Question 3

state 3 facts about the COM

Answer 3

1. the point where the mass of a body/system is evenly distributed
2. through which the line of action of weight can be assumed to act
3. linear kinematic quantities often refer to the COM of a body/system

Question 4

state what it is meant by the key term - ‘centre of mass’ (COM)

Answer 4

a point representing the mean position of the matter in a body or system

Question 5

when will an object not rotate ?

Answer 5

an object will not rotate if force is applied through the centre of mass

Question 6

how do you work out average velocity, and how do you work out instantaneous velocity ?

Answer 6

1. average = gradient of a chord

2. instantaneous = gradient of a tangent

Question 7

what is running described as ?

Answer 7

running (or other forms of gait) is a ‘cyclical’ form of human locomotion

Question 8

the kinematics of running can be described using what 3 parameters ?

Answer 8

1. stride / step length
2. stride / step frequency
3. velocity

Question 9

how can we use steps / strides to work out velocity ? (2 points)

Answer 9

1. Velocity (m/s) = stride length (m) x stride frequency (s)

2. Velocity (m/s) = step length (m) x step frequency (s)

Question 10

running velocity can be increased in what 3 ways ?

Answer 10

1. increasing SL
2. increasing SF
3. increasing both ?!?!

Question 11

what occurs between SL and SF at high velocities

Answer 11

at high velocities, there is a trade off between SL and SF

Question 12

state a fact about athletes in reference to SL and SF

Answer 12

athletes seem to be individually dependent on SL or SF for attaining maximum running velocities

Question 13

when a body experiences the same acceleration (magnitude and direction), the acceleration of that body is said to be what ?

Answer 13

constant (uniform)

Question 14

what are the 3 equations used to work out linear acceleration ?

Answer 14

1. v = u + at
2. s = (at) + (1/2 x a x t^2)
3. v^2 = u^2 + 2.a.s

Question 15

what is SUVAT ?

Answer 15

S - displacement (m/s)
U - initial velocity (m/s)
V - final velocity (m/s)
A - acceleration (m/s^2)
T - time (s)

Question 16

what is the difference between V and U ?

Answer 16

V = final velocity 
U = initial velocity

Question 17

what is the first equation to work out linear acceleration ?

Answer 17

v = u + at

Question 18

what is the second equation to work out linear acceleration ?

Answer 18

s = at + (1/2 x a x t^2)

Question 19

what is the third equation to work out linear acceleration ?

Answer 19

v^2 = u^2 + 2.a.s