Question

1. Jim drops a stone from the top of a five-storey building (a) How far has it fallen after 2 seconds? (b) What is the final velocity of the stone after 2 seconds of fall? (c) if the stone reaches the ground after 3 seconds, how high is the building? It is worth at this point to make a simple sketch.

2. How should the difference in mass, z = x - y, be reported? (Note that the symbol z now denotes the difference instead of the sum of two measurements).

Answer 1

1. (a) The distance traveled is

$$h=gt^2/2=19.6\text{ m}.$$

(b) The final velocity of the stone after 2 seconds of fall is

$$v=gt=19.6\text{ m/s}.$$

(c) The height of the building is

$$H=gT^2/2=44.1\text{ m}.$$

2. It should be reported with appropriate units of measurement.