They help scientists explain concepts that are difficult to observe.
Answer: 
Explanation:
Acceleration 
is expressed in the following formula:
Where:
is the final velocity of the projectile
is the initial velocity of the projectile
is the time
Solving:
This is the acceleration of the projectile
Answer:
The work done by the steam is 213 kJ.
Explanation:
Given that,
Mass = 5 kg
Pressure = 150 kPa
Temperature = 200°C
We need to calculate the specific volume
Using formula of work done
Where,R = gas constant
T = temperature
P = pressure
=Atmosphere pressure
m = mass
Put the value into the formula
Hence, The work done by the steam is 213 kJ.
Answer: You don't do work.
Explanation: If you don't do the work you don't have to ask this question. With work comes labor. With labor comes change. With change comes resistance and people do not like change. IT causes anger, so if you stop doing work and stick to the important supply like food, water, and shelter you don't have to go through the trouble of this and we can live in a peaceful environment for this world to be better than it is. People do to much, it's a natural fact but you can change the entire picture. If you read all of this thank you for accepting the fact of life.
Go and click to the invitation bar and you can find an option written as " search friends " . Then it's easy to find that unknown user if you're pretty fond with his/her username and DP ( display picture ).
