Answer:
v = 5030.4 m/s
Explanation:
let Fc be the centripetal force and Fg be the gravitational force of attraction on the satelite. let m be the mass of the satelite and M be the mass of earth.
At any point in the orbit, the satelite experiences forces , Fc and Fg such that:
Fc = Fg
m×v^2/r = G×M×m/(r^2)
m and r are the same throughout the equation,so that:
v^2 = G×M/(r)
v = \sqrt{G×M/(r)}
In a circular orbit, the displacement the satelite should cover is 2×π×r in a period :
T = 2×π×r /v
so that:
v = 2×π×r /T
then
2×π×r /T = \sqrt{G×M/(r)}
r = \sqrt[3]{T^2×G×M/(4×π^2)}
r = \sqrt[3]{(1.97×10^4)^2×(6.67408×10^-11)×(5.98×10^24)/(4×π^2)}
r = 15772060.56 m
then :
v = 2×π×r /T
= 2×π×(15772060.56) /(1.97×10^4)
= 5030.4 m/s
therefore, the satelite travels at a speed of 5030.4 m/s.
<span>The density of an object determines whether it will float or sink in another substance. An object will float if it is less dense than the liquid it is placed in.An object will sink if it is more dense than the liquid it is placed in.
Since the above solid sinks to the bottom it reflects that the object is less dense that the water.
Hope this answers your question</span>
Answer:
Second choice
Explanation:
I suppose ME is the same as POTENTIAL energy
ME = mgh = 70 * 10 * 12 = 8400j
Half way down, 4200 j is converted to Kinetic Energy
1/2 m v^2 = 4200
1/2 (70) v^2 = 4200 v = 10.95 m/s
Just before impact ALL of the 8400 j is now KE
1/2 (70)v^2 = 8400 v = 15.49 m/s
Answer:
Friction produces unnecessary heat leading to the wastage of energy. The force of friction acts in the opposite direction of motion, so friction slows down the motion of moving objects. Forest fires are caused due to the friction between tree branches. However, friction can also cause problems in a car. Friction between moving engine parts increases their temperature and causes the parts to wear down. Friction can be both harmful and helpful, so it may be necessary to decrease or increase friction.
