A bus was moving with a speed of 54 km/h. On applying brakes it stopped in 8 seconds. Calculate the acceleration.
Answers
SPEED (v) = 54KM/H = 54 X 1000 / 60 X 60 = 54000/3600 = 15M/S
TIME (t) = 8 SECS.
DISTANCE (s) = ?
SPEED = DISTANCE / TIME
15 = DISTANCE/8
15 X 8 = DISTANCE
120 = DISTANCE.
OR,
DISTANCE = 120 M.
NOTE:- SPEED IS SAME AS VELOCITY IN THIS CASE.
FOR ACCELERATION,
INITIAL VELOCITY (u) = O
FINAL VELOCITY (v) = 15M/S
TIME (t) = 8 SECS.
ACCELERATION (a) = v-u/t
= 15-0/8
=15/8
= 1. 875 M/S2.
In the above Question, the following information is given -
A bus was moving at a speed of 54 km/h. On applying brakes it stopped in 8 seconds.
To find -
Calculate the acceleration of the bus.
Solution-
Here,
A bus was moving at a speed of 54 km/h.
Now,
54 km
2w
=> 54 × ( 5 / 18 ) m/s
=> 15 m / s .
Hence, the initial Velocity of the bus is 15 m / s.
The bus stops finally.
Hence, the final velocity of my bus is 0 m / s.
Time is taken for the bus to stop = 8 seconds.
So, we know the following -
u = 15 m / s
V = 0 m / s
t = 8 s
Now, according to the first equation of motion -
V = u + at
=> 0 = 15 + 8 t
=> a= - ( 15 / 8 ) m / s²
=> a = -1.875 m / s²
The negative sign indicates that this is retardation...
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