One of Kepler's laws is that the orbits of planets are elliptical. It's not a suggestion.
BTW, circles are ellipses too, but so special that their likelihood is close to zero.
<u>Answer:</u> The velocity of released alpha particle is 
<u>Explanation:</u>
According to law of conservation of momentum, momentum can neither be created nor be destroyed until and unless, an external force is applied.
For a system:

where,
= Initial mass and velocity
= Final mass and velocity
We are given:

Putting values in above equation, we get:

Hence, the velocity of released alpha particle is 
Answer:
$893
Explanation: the complete question should be
The clothes washer in your house consumes 470 kWh of energy per year. Price of the washer is $360 and the lifetime of the washer is 10 yrs. Energy price in your city is 9 cents per kWh. What is the lifecycle cost of the clothes washer? (assume a maintenance cost of $11 per year)
SOLUTION
Given:
The clothes washe power consumption (PC) is 470 kWh
Price of the washer (P) is $360
lifetime of the washer (L) is 10 yrs
Energy price in the city (E) is 9 cents per kWh (Covert to $ by dividing 100)
maintenance cost (M) is $11 per year
Lifecycle cost = P + (PC × L × E) +M + L
Lifecycle cost = $360 + (470kWh × 10years × 9cents/100) + ($11 × 10years)
=$893
Answer: 20
Explanation: Mass number is the number of neutrons plus the number of protons. 8 + 12 gives 20.