Answer:

Explanation:
From the question we are told that:
Frictional force 
Coefficient of kinetic friction 
Generally the equation for Normal for is mathematically given by

Therefore


Answer:
If one cup falls down then there will be 59 cups left.
Answer:4kg
Explanation:
acceleration due to gravity(g)=10m/s^2
Weight(w)=40N
Weight=mass x g
40=mass x 10
Divide both sides by 10
Mass =40/10
Mass=4kg
Answer:
(A.)Nuclear fission and beta decay (electron emission)