An object is dropped from rest. What is its instantaneous speed when it has

been in motion for 5 s? The acceleration of gravity is 9.8 m/s2 .
Answer in units of m/s

Vf=vi+gt

V - gt = 9.8 * 5 = 49m/s.

To find the instantaneous speed of an object, given that it was dropped from rest and has been in motion for 5 seconds, we can use the equation of motion.

The equation we will use is:

v = u + at

Where:
v = instantaneous speed (what we're trying to find)
u = initial velocity (which is 0, as the object was dropped from rest)
t = time (which is 5 seconds)
a = acceleration due to gravity (which is -9.8 m/s^2, considering it's downward)

Substituting the values into the equation:

v = 0 + (-9.8) * 5

v = -49 m/s

The negative sign indicates that the object is moving in the downward direction. However, if we are looking for the magnitude of the speed (ignoring the direction), we simply take the absolute value:

|v| = |-49| = 49 m/s

Therefore, the instantaneous speed of the object after being in motion for 5 seconds is 49 m/s.