The formula for acceleration is the velocity times the inverse of time so it would be 21 times 1/13. So roughly 0.0769... is the acceleration(m/s^2).
<u>for instance, steel has a higher thermal conductivity than plastic. Hence, the steel plate gives away heat to the ice block faster than a plastic block does. As a result, ice melts faster on a steel plate than on a plastic one. Faster an object draws heat, the colder it feels.</u>
