Answer :
Answer:-0.8335m/s^2
Explanation:
To find the acceleration of the bus when it is brought to rest, we can use the formula relating acceleration, initial velocity, final velocity, and time:
=
−
a=
t
v
f
−v
i
where:
a is the acceleration,
v
f
is the final velocity (in this case,
=
0
v
f
=0 m/s because the bus comes to rest),
v
i
is the initial velocity,
t is the time taken.
Given:
Initial velocity,
=
60
v
i
=60 km/h,
Final velocity,
=
0
v
f
=0 m/s (since the bus comes to rest),
Time taken,
=
20
t=20 s.
First, convert the initial velocity from km/h to m/s:
=
60
km/h
=
60
×
1000
3600
m/s
v
i
=60 km/h=
3600
60×1000
m/s
=
16.67
m/s
v
i
=16.67 m/s
Now, calculate the acceleration:
=
−
=
0
−
16.67
20
m/s
2
a=
t
v
f
−v
i
=
20
0−16.67
m/s
2
=
−
16.67
20
m/s
2
a=
20
−16.67
m/s
2
=
−
0.8335
m/s
2
a=−0.8335 m/s
2
The negative sign indicates that the acceleration is in the direction opposite to the initial motion, which is deceleration (or negative acceleration).
Therefore, the acceleration of the bus while it is brought to rest by applying brakes is
−
0.8335
m/s
2
−0.8335 m/s
2
.