Answer:
I = 27kg.mi/h
Explanation:
In order to calculate the impulse of the ball, you use the following formula:
(1)
m: mass of the ball = 0.3kg
v: speed of the ball after the bat hit it = 60mi/h
vo: speed of the ball before the bat hit it = 30mi/h
You replace the values of all parameters in the equation (1):

where the minus sign of the initial velocity means that the motion of the ball is opposite to the final direction of such a motion.
The imulpse of the ball is 27 kg.miles/hour
Answer:
the energy difference between adjacent levels decreases as the quantum number increases
Explanation:
The energy levels of the hydrogen atom are given by the following formula:

where
is a constant
n is the level number
We can write therefore the energy difference between adjacent levels as

We see that this difference decreases as the level number (n) increases. For example, the difference between the levels n=1 and n=2 is

While the difference between the levels n=2 and n=3 is

And so on.
So, the energy difference between adjacent levels decreases as the quantum number increases.