Question

Velocity of a bus increases from 60 km/hr to 80 km/hr in 5 seconds. It's acceleration will be -
a. 1.1 m/s square
b. 2.2 m/s square
c. 3.3 m/s square
d. 11.0 m/s square​

Answer 1

Given :

• Initial velocity (u) = 60 km/h
• Final velocity (v) = 80 km/h
• Time (t) = 5 seconds

To find :

• Acceleration (a)

According to the question,

At first we will convert km/h into m/s

So,

The initial velocity (u) will be 16.6 m/s

And the final velocity (v) will be 22.2 m/s

Now, we will calculate acceleration by using Newton's first equation of motion,

→ v = u + at

Where,

• v stands for Final velocity
• u stand for Initial velocity
• t stands for Time
• a stands for Acceleration

→ Substituting the values,

→ 22.2 = 16.6 + a × 5

→ 22.2 - 16.6 = 5a

→ 5.5 = 5a

→ 5.5 ÷ 5 = a

→ 1.1 = a

.°. The acceleration is 1.1 m/s²

So,the option (a) 1.1 m/s² is correct.

_______________________________

More formula's :

Newton's first equation of motion :

• v = u + at

Newton's second equation of motion :

• s = ut + ½ at²

Newton's third equation of motion :

• v² = u² + 2as

Answer 2

Given:-

• Initial velocity (u)= 60 km/h = 50/3 m/s
• Final velocity (v) = 80 km/h = 200/9 m/s
• Time (t) 5 seconds

To Find:

Acceleration (a).

We know,

v = u + at

→ a = (v-u)/t

= [(200/9 - 50/3) m/s]/(5 s)

= [(200 - 150)/9 m/s]/(5 s)

= (50/9 m/s)/(5 s)

= (5.5 m/s)/(5 s)

= 1.1 m/s²

∴ ☑️ 1.1 m/s square