A fire hose sends 2429 gallons of water per minute against a burning building. The water strikes the building at 66 m/s and does
1 answer:
Answer:
a) Δp = - 10113.2 Kg m / s, b) he rate of change is negative, c) F = 140.46N
Explanation:
a) For this part let's analyze a water particle, it has a velocity of 66 m / s and when it collides with the building its velocity changes to zero, so the change in moment is
Δp = mv_f - m v₀
Δp = -m v₀ (1)
the change of the moment in a second is
if 2429 gallons arrive in in minute (60s) in a second how many gallons arrive
c_agua = 2429/60
c_water = 40,483 gallon/ s
let's use the concept of density to find the mass
ρ = m / V
m = ρ V
let's reduce gallons to liters
c_water = 40,483 gal (3,785 l / 1 gal) = 153.23 l
m = 1 153.23
m 153.23 kg
we substitute in 1
Δp = - 153.23 66
Δp = - 10113.2 Kg m / s
b) From the previous result the rate of change is negative
c) Let's use the impulse ratio
I = f t = Δp
F t = Δp
F = Δp / t
F =
F = 140.46 N
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Answer:
The ball experiences the greater momentum change
Explanation:
The momentum change of each object is given by:
where
m is the mass of the object
v is the final velocity
u is the initial velocity
Both objects have same mass m and same initial velocity u. So we have:
- For the ball, the final velocity is
Since it bounces back (so, opposite direction --> negative sign) with same speed (so, the magnitude of the final velocity is still u). So the change in momentum is
- For the clay, the final velocity is
since it sticks to the wall. So, the change in momentum is
So we see that the greater momentum change (in magnitude) is experienced by the ball.