Hi there!
The period of an orbit can be found by:

T = Period (? s)
r = radius of orbit (6400000 m)
v = speed of the satellite (8000 m/s)
This is the same as the distance = vt equation. The total distance traveled by the satellite is the circumference of its circular orbit.
Let's plug in what we know and solve.

Answer:
Explanation:
If the object is falling straight down it is in free fall. The difference between that and two-dimensional motion is that 2D motion is parabolic (projectile)
Answer:
The acceleration of the crate is
.
Explanation:
Given that,
Force, F = 750 N
Mass of the crate, m = 250 kg
The coefficient of friction is 0.12.
We need to find the acceleration of the crate. The net force acting on the crate is given by :

f is frictional force, 

So, the acceleration of the crate is
. Hence, this is the required solution.
Answer: The length of the shadow on the wall is decreasing by 0.6m/s
Explanation:
the specified moment in the problem, the man is standing at point D with his head at point E.
At that moment, his shadow on the wall is y=BC.
The two right triangles ΔABC and ΔADE are similar triangles. As such, their corresponding sides have equal ratios:
ADAB=DEBC
8/12=2/y,∴y=3 meters
If we consider the distance of the man from the building as x then the distance from the spotlight to the man is 12−x.
(12−x) /12=2/y
1− (1 /12x )=2 × 1/y
Let's take derivatives of both sides:
−1 / 12dx = −2 × 1 / y^2 dy
Let's divide both sides by dt:
−1/12⋅dx/dt=−2/y^2⋅dy/dt
At the specified moment:
dxdt=1.6 m/s
y=3
Let's plug them in:
−1/121.6) = - 2/9 × dy/dt
dy/dt = 1.6/12 ÷ 2/9
dy/dt = 1.6/12 × 9/2
dy/dt = 14.4/24 = 0.6m/s
Answer:
a) three times greater
Explanation:
Remember the heat capacity is the necessary heat to increase the temperature 1 ºC to an specific mass of the substance, in this case since the water and the metal have the same mass, is easier to compare just the neccesary heat.
Since water increases 20 ºC and the metal 60 ºC, it was neccesary 3 times of the quantity of heat to the same amount of mass of the two different susbtances.
Hope it was useful