A pillow is thrown downward with an initial speed of 6 m/s. After 4 seconds, the pillow's velocity is m/s. (g= -9.8m/s2)

The velocity of the pillow after 4 seconds is -45.2 m/sec and this can be determined by using the velocity formula.

Given :

A pillow is thrown downward with an initial speed of 6 m/s.

The equation of velocity is used in order to determine the pillow's velocity after 4 seconds.

v = u + at

where 'v' is the final velocity, 'a' is the acceleration due to gravity, 'u' is the initial velocity, and 't' is the time.

Now, substitute the known terms in the above equation in order to determine the pillow's velocity after 4 seconds.

v = -6 - 9.8 (4)

Simplify the above equation.

v = -6 - 39.2

v = -45.2 m/sec

So, the velocity of the pillow after 4 seconds is -45.2 m/sec.

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Given :

Initial velocity, u = -6 m/s.

Time taken, t = 4 seconds.

Acceleration due to gravity, .( Here negative sign means downward direction )

To Find :

Velocity after 4 seconds.

Solution :

By equation of motion.

v = u + at

Here , a = g.

v = u + gt

v = -6 + (-9.8)×4

v = -6 + (-39.2)

v = -45.2 m/s

Therefore, velocity after 4 seconds is -45.2 m/s.

Hence, this is the required solution.