Question

Q3. A car of mass 1000kg is moving with a
velocity of 40m/s. If velocity-time graph is a
horizontal line parallel to time axis then
velocity of car at the end of 25s will be:​

Answer 1

★ Solution :-

As per the given data ,

• mass of the car (m)= 1000 kg
• initial velocity of the car(u) = 40 m /s

We need to find the velocity of the car at the end of 25 sec i.e the final velocity of the car

In the question it is mentioned that the velocity - time graph is a horizontal line parallel to time axis

this means that the car is moving with uniform velocity throughout it's motion hence the acceleration of the car will be zero

→ v = 40 m /s

The velocity of the car at the end of 25 sec is 40 m /s

★ Additional formulas :-

First equation of motion ,

$\implies\boxed{\mathtt{v = u + at }}$

Second equation of motion ,

$\implies\boxed{\mathtt{s = ut + \dfrac{1}{2} a {t}^{2} }}$

Third equation of motion ,

$\implies\boxed{\mathtt{ {v}^{2} = {u}^{2} + 2as }}$

Distance covered by the body in n th second ,

$\implies\boxed{\mathtt{s_n= u + \dfrac{a}{2} (2n - 1)}}$

here ,

• v = final velocity
• u = initial velocity
• a = acceleration
• t = time taken
• s = distance
• n = time
• S n = Distance covered in n th second

These equations can only be used when the body moves with uniform acceleration