How can the magnetic field be seen around a wire?

a. using a battery
b. with an insulator
c. using iron filings
d. it is always visible

If a rock is thrown upward on the planet mars with a velocity of 12 m/s, its height (in meters) after t seconds is given by h = 12t − 1.86t2. (a) find the velocity of the rock after two seconds. m/s (b) find the velocity of the rock when t = a. 12−3.72a m/s (c) when will the rock hit the surface? (round your answer to one decimal place.) t = s (d) with what velocity will the rock hit the surface? m/s

Often called simply "velocity," this is the velocity of an object at a particular moment in time.

What are the necessary conditions for fusion?