Answer:

Explanation:
From the question we are told that:
Height of window 
Height of window off the ground 
Time to fall and drop
Generally the Newton's equation motion is mathematically given by

Where



Generally the Newton's equation motion is mathematically given by

Where





Therefore the ball’s initial speed

Answer:
The time taken to travel is, t = 12 minutes
Explanation:
Given data,
The speed of the car, v = 60 km/h
The distance of travel, d = 12 km
The time taken for the travel is t = ?
The speed is defined as the distance divided by the time taken to travel. The formula for speed is,
v = d/t
∴ t = d/v
t = 12 km / 60 km/h
t = 0.2 h
t = 12 minutes
Hence, the time taken to travel is, t = 12 minutes.
Answer:

Explanation:
The centripetal force acting on the car must be equal to mv²/R, where m is the mass of the car, v its speed and R the radius of the curve. Since the only force acting on the car that is in the direction of the center of the circle is the frictional force, we have by the Newton's Second Law:

But we know that:

And the normal force is given by the sum of the forces in the vertical direction:

Finally, we have:

So, the minimum value for the coefficient of friction is 0.27.
An element called Silica.