<u>Answer:</u>
Positive acceleration is in third hour and negative acceleration is in second hour.
<u>Explanation:</u>
Velocity of car in first hour = 70 mph
Velocity of car in second hour = 60 mph
Velocity of car in third hour = 80 mph
Acceleration = Change in velocity / Time
Acceleration in second hour = (60 - 70)/1 = -10 mph²
Acceleration in third hour = (80 - 60)/1 = 20 mph²
So positive acceleration is in third hour and negative acceleration is in second hour.
Let R be radius of Earth with the amount of 6378 km h = height of satellite above Earth m = mass of satellite v = tangential velocity of satellite
Since gravitational force varies contrariwise with the square of the distance of separation, the value of g at altitude h will be 9.8*{[R/(R+h)]^2} = g'
So now gravity acceleration is g' and gravity is balanced by centripetal force mv^2/(R+h):
m*v^2/(R+h) = m*g' v = sqrt[g'*(R + h)]
Satellite A: h = 542 km so R+h = 6738 km = 6.920 e6 m g' = 9.8*(6378/6920)^2 = 8.32 m/sec^2 so v = sqrt(8.32*6.920e6) = 7587.79 m/s = 7.59 km/sec
Satellite B: h = 838 km so R+h = 7216 km = 7.216 e6 m g' = 9.8*(6378/7216)^2 = 8.66 m/sec^2 so v = sqrt(8.32*7.216e6) = 7748.36 m/s = 7.79 km/sec
Atomic number is equal to the number of protons and electrons
Atomic mass - protons = neutrons
protons + neutrons = atomic mass
I hope this helps
