Answer:
3.9 seconds
Explanation:
Use constant acceleration equation:
y = y₀ + v₀ t + ½ at²
where y is the final position,
y₀ is the initial position,
v₀ is the initial velocity,
a is the acceleration,
and t is time.
Given:
y = 0 m
y₀ = 15 m
v₀ = 15 m/s
a = -9.8 m/s²
Substituting values:
0 = 15 + 15t + ½ (-9.8) t²
0 = 15 + 15t − 4.9t²
0 = 4.9t² − 15t − 15
Solve with quadratic formula:
t = [ -b ± √(b² − 4ac) ] / 2a
t = [ 15 ± √((-15)² − 4(4.9)(-15)) ] / 2(4.9)
t = [ 15 ± √(225 + 294) ] / 9.8
t = (15 ± √519) / 9.8
t = -0.79 or 3.9
It takes 3.9 seconds for the stone to reach the bottom of the well.
The negative answer is the time it takes the stone to travel from the bottom of the well up to the top of the well.
The answer to ur question is: B
The formula used in calculations relating to transformers
is:
<span>Secondary voltage
(Vs)/ Primary voItage (VP) = Secondary turns (nS)/
Primary turns (nP)</span>
Substituting the
given values to find for Vs,
Vs / 120 V = 400
turns / 100 turns
<span>Vs = 480 V</span>
Answer:
For the first one its about 25 feet
Explanation:
Answer:
D. The total energy of a system can increase only if energy enters the
system
energy must be conserved--it cannot be created or destroyed.
so, if the energy of a system increases, that energy must have come from somewhere
hope this helps!!
