Question

a car acquires a velocity of 72 km per hour in 10 seconds starting from the rest find the average velocity

Answer 1

HELLO THERE!

Given:

Final velocity of the car (v) = 72 km/h

[tex]= 72\times \frac{5}{18} msec^{-1} \\\\= 20 ms^{-1}[/tex]

Initial velocity (u) = 0 (since the car starts from rest).

Time in which the velocity is acquired with some acceleration a = 10 seconds.

Now, from the equation of motion:

[tex]v = u + at, \\\\\implies 20 = 0 + a\times10 \\\\\implies a = \frac{20}{10} ms^{-2} \\\\\implies a = 2 ms^{-2}[/tex]

Now from equation of motion:

[tex]S = ut + \frac{1}{2}at^{2}, \\\\\implies S = 0 + \frac{1}{2}\times2\times (10)^{2} \\\\\implies S = 100 m[/tex]

So, we get total displacement = 100 m.

Now,

Average velocity = Total displacement / Total time taken in achieving it

[tex]= \frac{100m}{10s} \\\\= 10 ms^{-1}[/tex]

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