An iron vise falls from rest at a great height. Neglecting air resistance, what is its speed after it has fallen for 5 seconds?

49 m/s

Explanation:

Given:

Time, t = 5 seconds

The vice falls from rest, therefore the initial velocity, u = 0.

We know acceleration due to gravity, g = 9.8 m/s2

Therefore, from equation of motion, we get

v = u + g. t

= 0 + (9.8 x 5)

= 49 m/s

Therefore the speed of the vice is 49 m/s after 5 second.