The object's speed will remain constant after the it leaves his hand.
So will HIS speed in the opposite direction.
The magnitude of a vector is the square root of its components squared. When you square a negative number, you will always get a positive number. Its like speed of your car. It will always be positive (or 0) whether you are moving forward or you are in reverse gear or stationary.
At a given moment in time, the instantaneous speed can be thought of as the magnitude of instantaneous velocity.
Instantaneous speed is the magnitude of the instantaneous velocity, the instantaneous velocity has direction but the instantaneous speed does not have any direction. Hence, the instantaneous speed has the same value as that of the magnitude of the instantaneous velocity. It doesn't have any direction.
Here are two leading theories to explain how the first galaxies formed. The truth may involve a bit of both ideas.
One says that galaxies were born when vast clouds of gas and dust collapsed under their own gravitational pull, allowing stars to form.
The other, which has gained strength in recent years, says the young universe contained many small "lumps" of matter, which clumped together to form galaxies. Hubble Space Telescope has photographed many such lumps, which may be the precursors to modern galaxies. According to this theory, most of the early large galaxies were spirals. But over time, many spirals merged to form ellipticals.
