You think you might have mixed your salt (NaCl) up with naphthalene (C10H8). You know that NaCl is safe to eat, but C10H8 is very dangerous. You need to find out which one is which before you put it on your lunch. Design an investigation in the space below that will help you determine which substance is NaCl and which one is C10H8. How will you determine which substance is NaCl and which one is C10H8?

Explain why you think this will work.​

1 the 4 is sig

if the person is shown to have +90n, then ans is -10n.

if the person is shown to have -90n, then ans is +10n.

see the picture for the vector

the magnitude of the vector by pythagorean theorem

r = √( (-10)^2 + (3)^2 ) = √109

magnitude = √109 units

the direction angle between vector and x-axis is

tan^(-1)(3/10) = 16.699

so the direction is approximately 16.7 degrees north of west

note: the given question is incomplete.

complete question is given below.

which is an example of kinetic energy?

a. the energy stored in ethanol  

b. a hockey puck sliding across the ice  

c. a compressed spring  

d. a ball sitting at the top of a ramp

solution: the kinetic energy is the energy posses by the virtue of the motion of the object.

in the given options, a, c and d are the example of potential energy because it is the energy posses by the virtue of the rest of the object. but option b has the kinetic energy as the object is in motion.

hence, a hockey puck sliding across the ice   is the apex example of kinetic energy.

so, the option (b) a hockey puck sliding across the ice   is the correct option.