Answer:

Explanation:
Given that
Mass of rifle = M
Initial velocity ,u= 0
Mass of bullet = m
velocity of bullet = v
Lets take final speed of the rifle is V
There is no any external force ,that is why linear momentum of the system will be conserve.
Initial linear momentum = Final linear momentum
M x 0 + m x 0 = M x V + m v
0 = M x V + m v

Negative sign indicates that ,the recoil velocity will be opposite to the direction of bullet velocity.
Answer:
Push -repulsion
Pull - attraction
Explanation:
When two magnets are brought together, a push happens when a force of repulsion is experienced where the magnets move away from each other. This means their polarity is the same and this will cause the magnet to push away from each other.
When two magnets are brought together , a pull happens when a force of attraction is experienced where the magnets move close to each other. This means their polarity is different and thus causes the magnets to pull closer to each other.
Based on the trend produced by the dose - response graph, it would be best to evacuate the residents in other to prevent the increasing percentage of deaths due to the rising level of pollutant A.
- The curve shows that the pollutant level in mg/kg of pollutant A is still increasing, hence, groundwater monitoring alone won't be the best decision to make.
- Since the pollutant level is still increasing, then the spill level still need effective monitoring.
- Evacuation of residents seems to be the best decision that should be taken based on the information interpreted on the graph.
Therefore, Evacuating residents to prevent rising death percentage is required as the pollutant level is yet to subside.
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