Question

A jet lands on an aircraft carrier at 30m/s. It stops in 2.0s. What is the
displacement of the plane when it stops?​

Answer 1

Answer:

→ v² = u² +2as. ∴ The displacement of the plane is 30 metres

Answer 2

Given :

• Initial velocity (u) = 30m/s
• Final velocity (v) = 0m/s (as the jet stops)
• Time taken (t) = 2 s

To Find :

• Displacement of the plane

Solution :

Firstly we calculate the acceleration of the jet. So using 1st equation of motion,

⇒ v = u + at

Substitute the value we get,

⇒ 0 = 30 + a × 2

⇒ a = -30/2

⇒ a = -15m/s

Here negative sign show retardation

∴ The acceleration of the jet is 15m/s²

And now using 3rd equation of motion,

⇒ v² = u² + 2as

Substitute the value we get,

⇒ 0² = 30² + 2 × (-15) × s

⇒ 0 = 900 + (-30) × s

⇒ -900 = -30 × s

⇒ s = -900/-30

⇒ s = 30m

∴ The displacement of the plane is 30 metres.