Answer:
True
Explanation
When an object slows down the Acceleration is in the other direction which “ slows it down
Answer: total mechanical energy of -4.6 x 10^10 j.
Explanation: the planet express is in a circular orbit around the earth and has a total mechanical energy of -4.6 x 10^10 j.
The total mechanical energy is the sum of potential energy and the kinetic energy.
For the rocket to experience the escape from earth, the total work done will be equal to maximum kinetic energy.
According to conservative of energy, maximum kinetic energy is equal to the total mechanical energy.
The work must be provided by the planet expresss rockets in order to completley escape earth will be equal to total mechanical energy of -4.6 x 10^10 j.
Answer:
Explanation:
Given that
Initial velocity wo=0.210rev/s
Then, 1rev=2πrad
wo=0.21×2πrad/s
wo=0.42π rad/s
Given angular acceleration of 0.9rev/s²
α=0.9×2πrad/s²
α=1.8π rad/s²
Diameter of blade
d=0.75m,
Radius=diameter/2
r=0.75/2=0.375m
a. Angular velocity after t=0.194s
Using equation of angular motion
wf=wo+αt
wf=0.42π+ 1.8π×0.194
wf= 0.42π + 0.3492π
wf=1.319+1.097
wf= 2.42rad/s
If we want the answer in revolution
1rev=2πrad
wf= 2.42/2π rev/s
wf=0.385 rev/s
b. Revolution traveled in 0.194s
Using angular motion equation
θf - θi = wo•t + ½ αt²
θf - 0= 0.42π•0.194 + ½ × 1.8π•0.194²
θf = 0.256 + 0.106
θf = 0.362rad
Now, to revolution
1rev=2πrad
θf=0.362/2π=0.0577rev
Approximately θf= 0.058rev
c. Tangential speed? At time 0.194s
Vt=?
w=2.42rad/s at t=0.194s
Using circular motion formulae, relationship between linear velocity and angular velocity
V=wr
Vt=wr
Vt= 2.42×0.375
Vt=0.9075 m/s
Vt≈0.91m/s
d. Magnitude of resultant acceleration
Tangential Acceleration is given as
at=αr
at=1.8π× 0.375
at=2.12rad/s²
Now, radial acceleration is given as
ar=w²r
ar=2.42²×0.375
ar=2.196 m/s²
Then, the magnitude is
a=√ar²+at²
a=√2.196²+2.12²
a=√9.3171
a=3.052m/s²
a≈ 3.05m/s²
Answer: Approximately 15,192 kilometers