According to the conservation of mechanical energy, the kinetic energy just before the ball strikes the ground is equal to the potential energy just before it fell.
Therefore, we can say KE = PE
We know that PE = m·g·h
Which means KE = m·g·h
We can solve for h:
h = KE / m·g
= 20 / (0.15 · 9.8)
= 13.6m
The correct answer is: the ball has fallen from a height of 13.6m.
Answer:
Winter
Explanation:
Earth Rotates about an axis
Explanation:
The given data is as follows.
Resistance (R) = 1200 ohm, Area (A) =
m (as
)
Diameter (d) = 2.3 mm =
m
First, we will calculate the length as follows.
R =
Here,
= resistivity of aluminium = 
Putting the given values above and we will calculate the value of length as follows.
R =
1200 = 
L = 
As the circumference of circular wire = 
or, =
= 
And, number of turns will be calculated as follows.
No. of turns × Circumference = Length of wire
No. of turns × 
= 
Thus, we can conclude that
turns of wire are needed.
By the use of a Accumulators
Answer:
v = 72 km / h
Explanation:
The definition of average speed is the distance traveled between the time interval
v = Δx / Δt
let's find the distance traveled
x = 60 + 30
x = 90 km
time spent, all time must be included, travel time and when stopped
t = 0.45 + 0.15 + 0.5+ 0.15
t = 1.25 h
we substitute in the initial equation
v = 90 / 1.25
v = 72 km / h
in going from one city to the other