Question

A body travels200m in tge first two seconds and 220m in the next 4 seconds.the velocity at the end of the seventh second is

Answer 1

IN FIRST CASE
BODY TRAVELLED 200 M IN 2 SEC
AND
IN SECOND CASE
BODY TRAVELLED (200+220) 420 M IN (2+4) SEC
NOW EQUATION OF CASE 1
200 = 2U + 1/2× A ×4
200 = 2U + 2A

NOW 2ND CASE
420 = 6U + 1/2× A ×36
420 = 6U + 18A
140= 2 U + 6 A
NOW SUBTRACTING 1 FROM 2
140 - 200 = 2U - 2U + 6A - 2A
- 60 = 4A
A = -15M/S^2
now As U + A = 100
therefore U = 115 m/s
NOW
V AT END OF 7TH SEC = STARTING OF 8TH SEC
V = U + AT
T =8
THEREFORE
V = 115 + (-15) × 8
V = 115 - 120
= -5 M/S

OR IF I AM MISTAKINGLY USING WRONG TIME THEN
V = 115 +(-15)7
V = 115 - 105
= 10 M/S
HOPE IT HELPS YOU