We are given –
Here–
[tex]\qquad[/tex][tex] \pink{\bf \longrightarrow Initial\: velocity = 100 \:km/hr}[/tex]
[tex]\qquad[/tex][tex] \sf \longrightarrow Initial\: velocity = \dfrac{ 100 \times 1000}{3600} \:m/s[/tex]
[tex]\qquad[/tex][tex]\pink{ \bf \longrightarrow Initial\: velocity = 27.78\: m/s} [/tex]
Now –
[tex]\qquad[/tex]____________________________
[tex]\qquad[/tex][tex] \purple{\bf \longrightarrow Acceleration = \dfrac{Final\: Velocity -Initial \:Velocity }{Time}}[/tex]
[tex]\qquad[/tex][tex] \purple{\bf \longrightarrow Acceleration = \dfrac{v -u}{t}}[/tex]
[tex]\qquad[/tex][tex] \sf \longrightarrow Acceleration = \dfrac{(0- 27.78)}{1800}[/tex]
[tex]\qquad[/tex][tex] \sf \longrightarrow Acceleration =\cancel{ \dfrac{- 27.78}{1800}}[/tex]
[tex]\qquad[/tex][tex] \purple{\bf \longrightarrow Acceleration = -0.015 \: m/s^2} [/tex]
[tex]\qquad[/tex]_______________________________