Answer: a) 456.66 s ; b) 564.3 m
Explanation: The time spend to cover any distance a constant velocity is given by:
v= distance/time so t=distance/v
The slower student time is: t=780m/0.9 m/s= 866.66 s
For the faster students t=780 m/1,9 m/s= 410.52 s
Therefore the time difference is 866.66-410.52= 456.14 s
In order to calculate the distance that faster student should walk
to arrive 5,5 m before that slower student, we consider the follow expressions:
distance =vslower*time1
distance= vfaster*time 2
The time difference is 5.5 m that is equal to 330 s
replacing in the above expression we have
time 1= 627 s
time2 = 297 s
The distance traveled is 564,3 m
At a point on the streamline, Bernoulli's equation is
p/ρ + v²/(2g) = constant
where
p = pressure
v = velocity
ρ = density of air, 0.075 lb/ft³ (standard conditions)
g = 32 ft/s²
Point 1:
p₁ = 2.0 lb/in² = 2*144 = 288 lb/ft²
v₁ = 150 ft/s
Point 2 (stagnation):
At the stagnation point, the velocity is zero.
The density remains constant.
Let p₂ = pressure at the stagnation point.
Then,
p₂ = ρ(p₁/ρ + v₁²/(2g))
p₂ = (288 lb/ft²) + [(0.075 lb/ft³)*(150 ft/s)²]/[2*(32 ft/s²)
= 314.37 lb/ft²
= 314.37/144 = 2.18 lb/in²
Answer: 2.2 psi
''When the quantity demanded intersect with quantity supplied, it leads o the formation of equilibrium point.''
<h3>How equilibrium occur?</h3>
The equilibrium price and equilibrium quantity occur where the supply and demand curves cross with each other. The equilibrium occurs when the quantity demanded is equal to the quantity supplied.
So we can conclude that when the quantity demanded intersect with quantity supplied, it leads o the formation of equilibrium point.
Learn more about equilibrium here: brainly.com/question/517289
Answer: 4 s
Explanation:
Given
The applied force is 70 N
mass of the rock is 28 kg
initial velocity 
final velocity 
Deceleration provided by force is
using the equation of motion
Answer:
Explanation:
using the law of the conservation of energy:
where K is the spring constant, x is the spring compression, N is the normal force of the block, 
is the coefficiet of kinetic friction and d is the distance.
Also, by laws of newton, N is calculated by:
N = mg
N = 3.35 kg * 9.81 m/s
N = 32.8635
So, Replacing values on the first equation, we get:
solving for :
