Question

a body travels 200 CM in first 2 seconds and 220 CM in next 5 second calculate the velocity at the end of the 7th second from the start

Answer 1

Acceleration of body is
a = 2S / t²
= (2 × 200 cm) / (2 s)²
= 100 cm/s²

Use equation of motion
v² - u² = 2aS

v = √(u² + 2aS)
= √[(0 m/s)² + (2 × 100 cm/s² × (200 cm + 220 cm))]
= 289.83 cm/s
≈ 3 m/s

∴ Velocity of body at the end of 7th second is approximately 3 m/s

Answer 2

$\textbf{Answer is in Attachment !}$