A roller-coaster car has a potential energy of 800 kJ and a kinetic energy of 170 kJ at point A in its travel. At the low point of the ride, the potential energy is zero, and 60 kJ of work have been done against friction since it left point A. What is the kinetic energy of the roller-coaster at this low point?

300

step-by-step explanation:

28-600w < 300

28-600w > 300

600-28w < 300

600-28w > 300

a 4/6 = 9/12   not proportional

step-by-step explanation:

to find which are not proportional, we can use cross products

if it is true, they are proportional.   if it is not true, they are not proportional.

a 4/6 = 9/12

4* 12 = 6*9

48 = 54

not this is not proportional  

b 2/3 = 12/18  

2* 18 = 3 * 12

36 = 36

this is proportional

c 5/4 = 10/8  

5*8 = 4*10

40 = 40

this is proportional

d 7/5 = 35/25

7*25 = 5 * 35

175 = 175

is proportional

need more info

step-by-step explanation:

what do you mean by "representation"? graph? table? etc.