Question

An object moving along a straight line at 12 m/s and undergoes an accelaraton of 9 m/s^2. After 4 seconds its speed will be a) 48 m/s
b) 14 m/s
c) 18 m/s
d) 24 m/s

Answer 1

Answer

The correct option is : (a) 48m/s

Given

• An object moving along straight line at 12m/s and undergoes an acceleration of 9m/s² .

To Find

• What will be its velocity after 4 seconds ?

Solution

Given ,

u = 12m/s

a = 9m/s²

We have from equations of motion,

$\sf\longrightarrow a =\dfrac{v - u}{t} \\\\ \sf\implies at = v - u \\\\ \sf\implies v = u + at \\\\ \sf\implies v = 12 + 9\times 4 \\\\ \sf\implies v = 12 + 36 \\\\ \sf\implies v = 48$

Therefore, after 4 seconds the speed of the object will be 48m/s

Answer 2

Hi there!

Your Answer :- 48m/s.

$\huge\sf\pink{☆\:Given \:☆ }$

Initial Velocity = 12m/s.

Time = 4sec.

Acceleration = 9m/s²

$\huge\sf\pink{☆\:Solution\:☆}$

Use First Equation of Motion.

$\red{v = u + at}$

$\green{v = 12 + 4(9)}$

$\purple{v = 12 + 36}$

$\boxed{v = 48 \: m {s}^{2} }$