Answer:
protons (+ charge) & neutrons (neutral charge)
however protons has a positive charge so it determined what atom it is.
Answer:
150 steps south
Explanation:
250 north 250 back to start then continue south for remainder of 400 steps. 150 south
Answer:
30 m/s
Explanation:
Speed is distance over time. 60 meters / 2 seconds, = 30 m/s.
We will define the Total mass to calculate the force, so our values are:
Total Mass 
The Weight is,

Through the hook's Law we calculate X.
, where x is the lenght of compression and K the Spring constant.
We don't have a K-Spring, but we can assume a random value (or simply let the equation in function of K)

I assume a value of 
