Question

A car speed increases from 40 km/hr to 60 km/hr in 5 sec. Calculate the acceleration of car.​

Answer 1

Answer:

$\frac{10}{9} \ m/s^{2}$

Explanation:

Given:

• Initial velocity of the car = u = 40 km/hr = 40 $\times \frac{5}{18} = \frac{100}{9} \ m/s$
• Final velocity of the car = v = 60 km/hr = 60$\times \frac{5}{18} = \frac{150}{9} \ m/s$
• Time = t = 5 seconds

To find:

• Acceleration of the car (a)

Using the first equation of motion, which says:

V=u+at

Substituting the values:

$\frac{150}{9} = \frac{100}{9} + a \times 5$

$\frac{150}{9}-\frac{100}{9} = 5a$

$\frac{50}{9} = 5a$

a = $\frac{50}{9} \times \frac{1}{5}$

a = $\frac{10}{9} \ m/s^{2}$

The acceleration of the car is equal to $\frac{10}{9} \ m/s^{2}$

Answer 2

Explanation :

A car increases its speed from 40 km/h to 60 km/h in 5 sec.

What is acceleration of car?

We have, initial speed = 40 km/h

⇒ Initial speed = 40 × (5/18) m/s

⇒ Initial speed = 11.11 m/s

____________________________

Now we have, final speed = 60 km/h

⇒ Final speed = 60 × (5/18) m/s

⇒ Final speed = 16.67 m/s

Now we know 1st equation of motion :-

⇒ v = u + at

Where,

• v denotes final speed
• u denotes initial speed
• a denotes acceleration
• t denotes time

Substituting values,

⇒ 16.67 = 11.11 + a × 5

⇒ 16.67 - 11.11 = 5a

⇒ 5.55 = 5a

⇒ a = 5.55/5

⇒ a = 1.11 m/s²

∴ Acceleration of car = 1.11 m/s²