Answer: 
The chromium nucleus will complete the reaction.
Explanation:
The given reaction is a type of radioactive nuclei decay:
Positron emission: It is a type of decay process, in which a proton gets converted to neutron and an electron neutrino. This is also known as
-decay. In this the mass number remains same.

Now according to the given reaction:

The chromium nucleus will complete the reaction.
Answer:
The object will travel at a constant rate in along a straight line.
Explanation:
In the given situation, it is mentioned that there is no external force acting on the given object. Thus, it will retain its initial velocity along a straight path.
Answer:
D) 735 J(oules)
Explanation:
Work is defined as force * distance
Force is defined as mass * acceleration
Given a mass of 15 kg and a gravitational acceleration of 9.8 m/s² since the box is being lifted up, the force being applied to the box is 15 kg * 9.8 m/s² = 147 N
Since the distance is 5 meters, the work done is 147 N * 5 m = 735 N/m = 735 J, making D the correct answer.
No. A mirror works because of reflection.
The final velocity of the pebble as it hits the ground is 21.5 m/s.
We have to use the equation;
v = u + gt
Where;
v = final velocity
u = initial velocity
g = acceleration due to gravity
t = time
Since the pebble was dropped from a height, u =0 m/s, hence,
v = gt
v = 9.8 ms-2 × 2.2 s
v = 21.5 m/s
Learn more about velocity: brainly.com/question/8898885