Question

A bus decreases its speed from
80 km h to 60 km h in 5 s.
Find the acceleration of the bus.​

Answer 1

Explanation:

u=80km/hr,

v=60km/hr

t=5s,

v=u+at

60km/hr=80km/hr+a×5sec,

60km/hr - 80km/hr=a×5sec,

-20km/hr=a×5sec,

a=-20km/hr=5sec,

a=-4km/hr/sec,

Therefore acceleration=-4km/hr/sec or -1.1m/s

Answer 2

Answer:

-1.11m/s

Explanation:

Given :

• Initial velocity,u = 80km/h

• Final velocity,v = 60km/h

• Time,t = 5s

To Find :

• Acceleration,a

Solution :

We know v = u + at

Put thier values and solve it.

$\Rightarrow \sf{} 60 =80 + a\times 5$

$\Rightarrow \sf{} 60 -80 =a\times 5$

$\Rightarrow \sf{} -20 =5a$

$\Rightarrow \sf{} -\dfrac{20}{5}=a$

$\therefore \sf{} a =-4km/h$

Convert -4km/h in m/s

So,

$\Rightarrow \sf{}\dfrac{- 4\times1000}{1\times60\times60}$

$\Rightarrow \sf{}-\dfrac{4000}{3600}$

$\sf{}\Rightarrow -1.11m/s$

Hence,accecelation is equal to -1.11m/s