Question

Brakes applied to a bus produce a deceleration of 10m/s2. If the bus takes 5 seconds to stop, calculate the distance it travels during the time.
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Answer 1

Answer:

Given:

Accerleration: a=−6 m/s

2

Time t=2 s

Final velocity, v=0 m/s

v=u+at

0=u−6×2

u=12 m/s

s=ut+

2

1

at

2

s=12×2+

2

1

×(−6)×4

⇒s=12 m

Answer 2

Answer :-

• The bus will travel 125 m during the time.

Given :-

Acceleration of bus = -10 m/s²

Final velocity of bus = 0 m/s

Time taken by bus = 5 s

To Find :-

Distance travelled by the bus during that time

Solution :-

❍ To calculate the initial velocity of the bus we have to substitute the values in the first equation of motion :

v = u + at

Where,

• v denotes final velocity  
• u denotes initial velocity
• t denotes time

Finding the initial velocity :-

⤳ 0 = u + ( - 10  × 5 )    

⤳ 0 = u + ( - 50 )  

⤳ 0 = u - 50  

⤳ u = 0 + 50  

⤳ u= 50 m/s

• Henceforth, the initial velocity of the bus is 50 m/s

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❍  To calculate the distance travelled by the bus we have to substitute the values in the second equation of motion ::

s = ut + ½ at²

Where,

• s denotes distance

• u denotes initial velocity

• a denotes acceleration

• t denotes time taken

Finding the distance travelled :-

⤳ s = [ 50 × 5 ] + ½  × -10 × 5²

⤳ s = 250 + ½  × -10 × 25

⤳ s = 250 + [ - 5 × 25 ]

⤳ s = 250 + [ - 125 ]

⤳ s = 250 - 125

⤳ s = 125 m

• Henceforth, the distance travelled by the bus is 125 m