Answer:
171.5 N
Explanation:
The gravitational force on an object due to the Earth is given by

where
m is the mass of the object
g is the acceleration due to gravity
The acceleration due to gravity at a certain height h above the Earth is given by

where:
G is the gravitational constant
is the Earth's mass
is the Earth's radius
Here,

So the acceleration due to gravity is

We know that the mass of the object is
m = 70 kg
So, the gravitational force on it is

The time for half the atoms in a radioactive substance to disintegrate
https://www.vocabulary.com/dictionary/half-life
The time must be measured with respect to gravity. As it falls, it has free fall that is the force acting on it will be the gravity.With the distance in account, d = 1/2 gt²
t = √(2d/g)
Answer:
Your friend is 2.143 blocks from the restaurant.
You are 2.857 blocks from the restaurant.
Explanation:
Let t be the time both you and your friend take to walk to the restaurant.
The distance (m) from your building to the restaurant is your walking time t times your speed v1

Similarly the distance (m) from your friend building to the restaurant:

Let b be the length (in m) of a block, the total distance of 5 blocks is 5b





So your friend are 2.143b meters from the restaurant, since each block is b meters long, 2.143b meters would equals to 2.143b/b = 2.143 blocks. And you are 5 - 2.143 = 2.857 blocks from the restaurant.