Question

A car starts from rest and attains a speed of 36km/h in 2 sec. calulate velocity of in 5 sec.​

Answer 1

Given

A car starts from rest and attains a speed of 36 km/h in 2 sec

To Find

Velocity in 5 sec

Solution

We know that

Calculating acceleration

Equation of motion

$\sf \longrightarrow v=u+at$

Given that

A car starts from rest and attains a speed of 36 km/h in 2 sec

Hence

• u = 0 m/s [starts from rest]
• v = 36 km/h = 10 m/s
• t = 2 s

Substituting the values

We get

$\sf \longrightarrow 10=0+a(2)$

$\sf \longrightarrow 10=0+2a$

$\sf \longrightarrow 2a=10$

$\sf \longrightarrow a=\dfrac{10}{2} \ m/s^{2}$

Hence

$\sf \longrightarrow a = 5 \ m/s^{2}$

Calculating velocity in 5 sec

According to the question

We are asked to find velocity in 5 sec

Therefore

• t = 5 s

Given that

• u = 0 m/s [starts from rest]

We found out that

• a = 5 m/s²

Substituting the values in above given equation

We get

$\sf \longrightarrow v=0+5 \times 5 \ m/s$

$\sf \longrightarrow v=5 \times 5 \ m/s$

Therefore

$\sf \longrightarrow v=25 \ m/s$

Hence

Velocity in 5 sec = 25 m/s

Answer 2

Answer:

Given :-

• A car starts from rest and attains a speed of 36 km/h in 2 seconds.

To Find :-

• What is the final velocity in 5 seconds.

Formula Used :-

❶ To find acceleration we know that,

✰ a = v - u/t ✰

❷ To find velocity we know that,

★ v = u + at ★

where,

• v = Final velocity
• u = Initial velocity
• a = Acceleration
• t = Time

Solution :-

❶ First we have to find the acceleration,

Given :

• v = 36 km/h = 10 m/s
• u = 0 m/s
• t = 2 seconds

According to the question by using the formula we get,

⇒ a = 10 - 0/2

⇒ a = 10/2

➠ a = 5 m/s²

Hence, the acceleration is 5 m/s² .

❷ Now we have to find velocity,

Given :

• a = 5 m/s²
• u = 0 m/s
• t = 5 seconds

According to the question by using the formula we get,

↦ v = 0 + (5)(5)

↦ v = 0 + 25

➦ v = 25 m/s

∴ The velocity in 5 seconds is 25 m/s .