A satellite of mass `1000 kg` is supposed to orbit the earth at a height of `2000 km` above the earth's surface. Find `a.` its speed in the orbit `b`. its kinetic energy. `

Answer

A, B, C, D

Explanation

`V=(sqrt(GM)/(r+h))=(sqrt(gr^2)/(r+h))`
`(sqrt(9.8xx(6400xx10^3)^2))/(10^6xx(6.4+2)))`
`(sqrt(9.8xx6.4xx6.4xx10^6)/8.4)`
`=6.9xx1063m/s=6.9km/s`
b. K.E. =1/2mv^2`
`=1/2xx1000xx(47.6xx10^6)`
`=2.38xx10^10J`
c. P.E. `=(GMm)/(-(R+h))`
`=-(6.67xx10^-11xx6xx10^24xx10^3)/((6400+2000)xx10^3)`
`=(40xx10^13)//400=-4.76xx10^10J`
d. `T=(2pi(r+h))/V`
`=(2xx3.14xx8400xx10^3)/(6.9xx10^3)`
`=(6.28xx8xx10^2)/6.9`
`=76.6xx10.2sec`
`=2.1hours`