Question

a certain force exerted for 1.2 seconds rises the speed of an object from 1.8 m/s to 4.2 m/s. later the same force is applied for 2 seconds.
How much does the velocity change in two seconds?

Answer 1

The force applied for 1.2 sec changes the velocity from 1.8m/s to 4.2m/s.

So, the acceleration produced by the force

$= \frac{(4.2 - 1.8)}{1.2} \\ = \frac{2.4}{1.2} \\ = 2m {s}^{ - 2}$


⏩Now again the same force is applied after the body gains a velocity 4.2m/s , so it will produce the same acceleration, that is 2m/s²

In this case, initial velocity (u) = 4.2m/s

acceleration (a) = 2m/s²

and time (t) = 2sec

Using the 1st equation of motion,

v = u + at

v = 4.2 + 2(2)

= 4.2 + 4 = 8.2m/s

Therefore, the velocity changes to 8.2m/s



★★ HOPE THAT HELPS ☺️ ★★

Answer 2

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