Momentum is conserved if and only if sum of all forces which are exserted on system equals zero. In our situation there are only internal forces, so by Newton's third law their vector sum is 0.

So $mv=(m+M)v' \Leftrightarrow v'=\frac{mv}{m+M}$ .

Kinetic energy of system at first: $\frac{mv^2}{2}=784\;\textbf{J}$ . After: $\frac{(m+M)\frac{m^2v^2}{(m+M)^2} }{2}=\frac{m^2v^2}{2(m+M)}\approx 1,96\; \textbf{J}$ . The secret is that other energy is in work of deformation forces (they in turn heat a bullet and a block).

Answer is A)

5 0

3 years ago

The American Psychological Association is the only organization that can approve psychological research studies.

pav-90 [236]

Answer: This is False.

Explanation:

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3 years ago

Cohort studies allow the investigator to examine multiple outcomes and multiple exposures. Consider the following three exposure

mojhsa [17]

Answer:

See the explanation for the answer.

Explanation:

Cohort study for smoking

Outcomes that were examined

1. People at risk of lung cancer due to smoking

2. Influence of outdoor air pollution in lung cancer

3. Variation in tobacco smoking and heavy tobacco smoking was observed.

4. Occupational factors and housing factor were observed.

Cohort study for low vitamin D

Outcomes that were examined

1. People at risk of vitamin D deficiency.

2. Observing value in summer.

3. Correlating vitamin D value with weather and age

4. 25-hydroxy vitamin D was observed.

Cohort study for cold weather

Outcomes that were examined

1. Allergic and asthma risked people were observed.

2. effect on the people when temperature goes up.

3. Observation on the most harsh weather day.

4. Correlating it with age and analysis.

3 0

3 years ago