A20 kg object is dropped from a very tall building. what is the weight of this objects? after 5 seconds, how has the object fallen and what is its speed at this instant?

1. What is the weight of this objects?

Weight is simply the product of mass and gravitational acceleration. Therefore the weight is:

w = 20 kg * 9.81 m/s^2

w = 196.2 kg m/s^2 = 196.2 N

2. After 5 seconds, how has the object fallen and what is its speed at this instant?

We can use the formula:

y = v0 t  + 0.5 g t^2

v = v0 + g t

where v0 = 0 since the object starts from rest, y is the distance it fell, t is time

y = 0 + 0.5 * 9.81 * 5^2 = 122.625 m

v = 0 + 9.81 * 5 = 49.05 m/s