Answer:
9 cm.
Explanation:
The energy used for stretch the spring from
to
will be ,
The energy used for stretch the spring from
to
will be ,
using the energy of spring formula ,we find that


Dividing both the equation will get,

Therefore, the natural length of the spring is, 9 cm.
Answer:
The speed of meteoroid is 21.61 km/s in south-east.
Explanation:
Given that,
A meteoroid is traveling through the atmosphere at 18.3 km/s. while descending at a rate of 11.5 km/s it means 11.5 km/s in south.
We need to draw a diagram
Using Pythagorean theorem




Hence, The speed of meteoroid is 21.61 km/s in south-east.
Answer:
the earth is flat, the stars control human life, the planets revolve around the earth
Explanation:
Newton's 2nd law says: Force = (mass) x (acceleration) .
I wrote Force and acceleration in bold letters because
they're both vectors ... they have size and direction.
The equation is saying that the Force and the acceleration
are both in the same direction.