If a block is already put in motion, which of the following statements apply? The force needed to overcome the sliding friction is less than the force needed to overcome the starting friction.
The force needed to overcome the sliding friction is equal to the force needed to overcome starting friction.
The force needed to overcome the sliding friction is greater than the force needed to overcome the starting friction.
No force is needed to overcome sliding friction once force has been applied to overcome the starting frictio

The correct answer is  "c".  it is "c" because melting is an endothermic change, and endothermic get's energy from surroundings. 

Answershe should not have multiplied the sulfur atoms by the subscript 4

B) erini just took the test and it is correct

Since you have not included the experiment situation and the data, of course, i can not give you specific details about it. but i can you with this question.1) i will assume that the motion is projectile (parabolic) motion.2) yes, the horizontal distance depends on the horizontal velocity as, naming vx the horizontal velocity and t the time, it is: x = vx × t3) now, observe that the flight time depends on the vertical velocity as, naming voy the initial vertical velocity, t the time and y the vertical distance before reaching the ground: y = yo + voy×t - gt² / 2.the higher the initial vertical velocity (voy) the longer the object will be flying and so t will be higher in the equation for the horizontal distance.that explains the relationship between the horizontal distance and the horizontal velocity.