Question

In 1994, a tower 22.13 meter tall was built of Lego blocks. Suppose a block with a mass of 2.00 grams is dropped from the top of this tower. Neglecting air resistance, calculate the block's momentum at the instant the block hits the ground.

Answer 1

0.042 kg m/s

Step-by-step explanation:

In order to solve this, we need to find the final velocity of the block at the moment it its the ground.

The motion of the block is a free fall motion, so it is a uniform accelerated motion, so we can use the following suvat equation:

`v^2-u^2=2as`

where:

v is the final velocity

u = 0 is the initial velocity (it starts from rest)

`a=g=9.8 m/s^2` is the acceleration of gravity (we chose downward as positive direction)

s = 22.13 m is the displacement

Solving for v,

`v=√(u^2+2as)=√(0+2(9.8)(22.13))=20.8 m/s`

Now we can find the final momentum of the block, using the equation:

p = mv

where

m = 2.0 g = 0.002 kg is the mass of the block

Substituting,

`p=(0.002)(20.8)=0.042 kg m/s`