Spectroscopy — the use of light from a distant object to work out the object is made of — could be the single-most powerful tool astronomers use, says Professor Fred Watson from the Australian Astronomical Observatory. ... "It lets you see the chemicals being absorbed or emitted by the light source.
You must observe the object twice.
-- Look at it the first time, and make a mark where it is.
-- After some time has passed, look at the object again, and
make another mark at the place where it is.
-- At your convenience, take out your ruler, and measure the
distance between the two marks.
What you'll have is the object's "displacement" during that period
of time ... the distance between the start-point and end-point.
Technically, you won't know the actual distance it has traveled
during that time, because you don't know the route it took.
Answer:
<em>a = 7.6\ mph/s</em>
Explanation:
<u>Motion With Constant Acceleration
</u>
It's a type of motion in which the velocity of an object changes uniformly in time.
The equation that describes the change of velocities is:

Where:
a = acceleration
vo = initial speed
vf = final speed
t = time
Solving the equation [for a:

The car accelerates from vo=0 to vf=60 mph in t=7.9 s, thus the acceleration is:

a = 7.6\ mph/s