Answer:
0 N.
Explanation:
Force: This can be defined as the product of mass and the acceleration of the body. The S.I unit of force is Newton (N).
The expression of net force when both force act in the different direction is given as
F' = W-F ........................ Equation 1
Where F' = Net force on the bag, W = gravitational force on the bag, F = Force acting upward on the bag
Given: W = 18 N, F = 18 N.
Substitute into equation 1
F' = 18-18
F' = 0 N.
Hence the net force = 0 N.
A- Radio waves, is the answer
The radiation that was emitted is still "visible"
The universe is still expanding
Dark matter could only be crated by an atomic collapse big enough to create or destroy a universe
Answer:
The critical stress required for the propagation of an initial crack 
= 21.84 M pa
Explanation:
Given data
Modulus of elasticity E = 225 × 
Specific surface energy for magnesium oxide is 
= 1 
Crack length (a) = 0.3 mm = 0.0003 m
Critical stress is given by 
= 
-------- (1)
⇒ 2 E = 2 × 225 × × 1 = 450 ×
⇒ 
a = 3.14 × 0.0003 = 0.000942
⇒ Put these values in equation 1 we get
⇒ = 
⇒ = 4.77 × 
⇒ = 2.184 × 
⇒ = 21.84 
⇒ = 21.84 M pa
This is the critical stress required for the propagation of an initial crack.
Density is equal to mass divided my volume, so divide 38.6 by 2 to get the answer you need!
