140 PRINT "Press any key for a definition of FRICTION."
150 GET KY$
160 HOME
165 PRINT : PRINT : PRINT : PRINT
170 PRINT "FRICTION forces are forces that oppose motion.
172 GOSUB 1000
174 PRINT : PRINT : PRINT
180 PRINT " FRICTION is caused by the irregularities of any two contacting surfaces."
182 GOSUB 1000
184 PRINT : PRINT : PRINT
190 PRINT "So... the smoother the surface, the less the friction."
192 PRINT : PRINT : PRINT
194 GOSUB 1000
200 PRINT : PRINT "Press any key for an example."
210 GET KY$
250 HOME
252 PRINT : PRINT
254 PRINT " xxx"
256 PRINT " x x"
258 PRINT " xx xxxx"
260 PRINT " x x"
262 PRINT " xxx xxxxxxx xxx"
264 PRINT " O O"
270 PRINT : GOSUB 1000
280 PRINT "You're in a car. "
282 GOSUB 1010
284 PRINT : PRINT "You have to hit the brakes fast."
286 GOSUB 1010
290 PRINT : PRINT "On which kind of surface will you stop most quickly?"
300 PRINT : PRINT
310 PRINT " a. A dry road"
312 PRINT " b. A wet road"
314 PRINT " c. An icy road "
316 PRINT " d. It doesn't matter."
318 PRINT : GET KY$
320 HOME : PRINT : PRINT : PRINT : PRINT : PRINT
330 IF KY$ = "a" OR KY$ = "A" THEN PRINT "RIGHT!! That's because a dry road has more friction.": GOSUB 1030: PRINT CHR$(4);"run qs6"
340 IF KY$ = "b" OR KY$ = "B" THEN PRINT "NO, you wouldn't stop faster on a wet surface! Try again.": GOSUB 1030: GOTO 250
350 IF KY$ = "c" OR KY$ = "C" THEN PRINT "Wrong! I hope you don't have a driver license. Try another answer.": GOSUB 1030: GOTO 250
360 IF KY$ = "d" OR KY$ = "D" THEN PRINT "Nope! It does make a difference. Think about it and try again.": GOSUB 1030: GOTO 250
370 IF KY$ < >"b" OR KY$ < >"B" OR KY$ < >"c" OR KY$ < >"C" OR KY$ < >"d" OR KY$ < >"D" THEN PRINT "Please enter <a>, <b>, <c>, or <d>!!!!": GOSUB 1000: GOTO 250