Cooper Section $8\mathrm{.}5\backslash$#$2$

The height of an airplane above the ground when it has flown $\backslash ($ x $\backslash )$ miles is $\backslash ($ h$($x$)\backslash )$ feet.

a$.$ What are the units of $\backslash ($ h$^\{\backslash$prime$\}($x$)\backslash )?$

A$.$ miles per foot

B$.$ feet per hour

C$.$ foot$-$miles

D$.$ feet per mile

E$.$ unitless

b$.$ What is the meaning of the statement that $\backslash ($ h$^\{\backslash$prime$\}(10)=500\backslash )?$

A$.$ After $11$ miles the plane is $500$ feet higher than it was after $10$ miles.

B$.$ The plane rises $10$ feet for every $500$ miles it flies.

C$.$ The plane rises $500$ feet for every mile it flies.

D$.$ The plane rises $10$ feet for every mile it flies.

E$.$ When the plane has flown $10$ miles it is rising at a rate of $500$ feet per mile of flight.

F$.$ When the plane has flown $10$ miles it is rising at a rate of $500$ feet per $10$ miles of flight.

G$.$ The plane rises $500$ feet for every $10$ miles it flies.

c$.$ During which part of the flight would you expect $\backslash ($ h$^\{\backslash$prime$\}($x$)\backslash )$ to be negative?

A$.$ descent

B$.$ deceleration

C$.$ acceleration

D$.$ ascent

E$.$ cruising

d$.$ What would it mean if $\backslash ($ h$^\{\backslash$prime$\}($x$)\backslash )$ were negative?

A$.$ The plane is losing altitude.

B$.$ The plane is gaining altitude.

C$.$ The plane is gaining speed.

D$.$ The plane is losing speed.

E$.$ The plane is getting colder.

F$.$ The plane is taking off.