Question

velocity of an aircraft is changing from 20m/s to 10m/s in 2 second calculate acceleration

Answer 1

Provided that:

• Initial velocity = 20 mps
• Final velocity = 10 mps
• Time = 2 seconds

To calculate:

• The acceleration

Solution:

• The acceleration = -5 m/s²

Using concept(s):

• We can solve this question by using either acceleration formula or the first equation of motion.

• Choice may vary!

Using formula(s):

• Acceleration formula:

• a = (v-u)/t

• First equation of motion:

• v = u + at

Where, a denotes acceleration, v denotes final velocity, u denotes initial velocity, t denotes time.

Required solution:

~ Finding retardation by using acceleration formula firstly!

→ a = (v-u)/t

→ a = (10-20)/2

→ a = -10/2

→ a = -5 mps sq.

→ Retardation = -5 mps sq.

~ Now by using first equation of motion let us calculate the acceleration!

→ v = u + at

→ 10 = 20 + a(2)

→ 10 = 20 + 2a

→ 10 - 20 = 2a

→ -10 = 2a

→ -10/2 = a

→ -5 = a

→ a = -5 mps sq.

→ Retardation = -5 mps sq.

Additional information:

$\begin{gathered}\boxed{\begin{array}{c}\\ {\pmb{\sf{Three \: equation \: of \: motion}}} \\ \\ \sf \star \: v \: = u \: + at \\ \\ \sf \star \: s \: = ut + \: \dfrac{1}{2} \: at^2 \\ \\ \sf \star \: v^2 - u^2 \: = 2as\end{array}}\end{gathered}$

Answer 2

• initial velocity=u=20m/s
• Final velocity=v=10m/s
• Time=t=2s

We know

$\boxed{\sf Acceleration=\dfrac{v-u}{t}}$

$\\ \sf\longmapsto Acceleration=\dfrac{10-20}{2}$

$\\ \sf\longmapsto Acceleration=\dfrac{-10}{2}$

$\\ \sf\longmapsto Acceleration=-5m/s^2$