3.1.2 linear motion

Question 1

what are the 5 equations of motion?

Answer 1

v = u + at
s = 1/2(u+v)t
s = ut +1/2at^s
s = vt - 1/2at^2
v^2 = u^2 + 2as

Question 2

derive v = u + at

Answer 2

rearrange equation for gradient of a velocity-time graph where
a = (v-u)/t

Question 3

derive s = ut +1/2at^2

Answer 3

area under v-t graph = ut + 1/2(v - u)t
v - u = at (from equ 1)
sub in

Question 4

derive 1/2(u+v)t

Answer 4

use trapezium rule A = 1/2(a+b)h

Question 5

derive v^2 = u^2 +2as

Answer 5

t = (v-u)/a (from equ 1)
sub t into equ 3
rearrange

Question 6

what techniques can be used to practically analyse motion?

Answer 6

• trolleys
• air-track gliders (reduce the effect of friction)
• ticker timers (put dots on tape every 1/50th of a second so count the GAPS, not the dots)
• light gates (measures speed when an object passes through it)
• data loggers (sensor receives info and is stored by comp chip)
• video techniques (keep ruler in frame for distance and time on video)