Michelle melted a compound in the lab and performed the same procedure five times. the chart below shows the time it took for the compound to melt during the five trials.

trial time (min: sec)
1 3: 14
2 3: 10
3 4: 05
4 3: 12
5 3: 09

after reviewing her data, she realized that trial 3 was vastly different from the other four trial times. which of the following reasons could explain the radical difference in melting time for trial 3?

a larger quantity of compound was used in trial 3.
the compound started at a lower temperature in trial 3.
the burner was not directly under the compound during trial 3.
all of these

Ithink the answer is fusion 

The figure is missing but we can answer anyway.the correct answer is "releasing the string". in fact, when the person is holding the bow and the arrow, the kinetic energy of the arrow is still zero (because the arrow is not moving). the moment the arrow is released, it acquires a velocity v, so its kinetic energy will become different from zero: where m is the mass of the arrow and v its velocity.  all the other options, instead, do not increase the kinetic energy of the system: -  pulling farther back on the string : this will just increase the elastic potential energy of the system-  holding the arrow higher: this will increase the gravitational potential energy of the system (which is given by u=mgh, where h is the height above the ground)-  decreasing the mass of the arrow: this will decrease the gravitational potential energy of the system (which is given by u=mgh, where m is the mass)