Answer:
The speed of the ball when it hits the ground is 102.1 m/s
Explanation:
Given;
initial velocity of ball, u = 25 m/s
distance traveled by the ball = height of the building = h = 500 m
when the ball hits the ground, the final velocity, v = ?
The final velocity of the ball is given by;
v² = u² + 2gh
where;
g is acceleration due to gravity = 9.8 m/s²
v² = (25)² + 2(9.8)(500)
v² = 10425
v = √10425
v = 102.1 m/s
Therefore, the speed of the ball when it hits the ground is 102.1 m/s
Answer:

Explanation:
We have,
Mass of Mars is, 
Mass of its moon Phobos, 
Distance between Mars and Phobos, d = 9378 km
It is required to find the gravitational force between Mars and Phobos. The force between two masses is given by

Plugging all values, we get :

So, the gravitational force is
.
Answer:
The magnetic flux through the desk surface is
.
Explanation:
Given that,
Magnetic field B = 0.42 T
Angle =68°
We need to calculate the magnetic flux

Where, B = magnetic field
A = area
Put the value into the formula



Hence, The magnetic flux through the desk surface is
.
I am not completely sure, but I believe that it depends on the total mass of the Protons and Neutrons
"Constant velocity" is practically a definition for zero acceleration.