Answer:
v= 2413.5 m/s
Explanation:
maximum change of speed of rocket
=(initial exhaust velocity)×ln [(initialmass/finalmass)]
let initial mass= m
final mass = m-m(4/5) = m/5
[since the 80% of mass which is fuel is exhausted]
V-0 = 1500 ln (1/0.2)
V= 1500×1.609 = 2413.5 m/s
therefore, its exhaust speed v= 2413.5 m/s
W=ΔKE , W=-5000j
KEinitial=(1/2)mv² , KEfinal=0j
ΔKE=-(1/2)mv²
-5000=-(1/2)(100kg)v²
v=10 m/s
Answer:
t₁ = 0.95 s
Explanation:
In this chaos we must use the definition of Newton's second law
F = m a = m dv / dt
dv = F dt / m
Let's replace and integrate, let's take the upward direction of the plane as positive, the force is positive
dv = ∫ (3 + 2t) dt / m
v = (3 t + 2 t²/ 2) /m
Let's evaluate between the lower limit t = 0 v = -6 ft / s (going down) to the upper limit t = t and v = 0
0 - (-6) = (3 (t- 0) + (t² -0)) / m
t² + 3t -6m = 0
Let's look for the mass
W = mg
m = W / g
m = 20/32
m = 0.625 slug
Let's solve the second degree equation
t² + 3t -3.75 = 0
t = (-3 ± √ (32 + 4 1 3.75)) / 2
t = (-3 ± 4,899) / 2
t₁ = 0.95 s
t₂ = -3.95 s
We take the positive time
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Answer:
It takes you 32.27 seconds to travel 121 m using the speed ramp
Explanation:
<em>Lets explain how to solve the problem</em>
- The speed ramp has a length of 121 m and is moving at a speed of
2.2 m/s relative to the ground
- That means the speed of the ramp is 2.2 m/s
- You can cover the same distance in 78 seconds when walking on
the ground
<em>Lets find your speed on the ground</em>
Speed = Distance ÷ Time
The distance is 121 meters
The time is 78 seconds
Your speed on the ground = 121 ÷ 78 = 1.55 m/s
If you walk at the same rate with respect to the speed ramp that
you walk on the ground
That means you walk with speed 1.55 m/s and the ramp moves by
speed 2.2 m/s
So your speed using the ramp = 2.2 + 1.55 = 3.75 m/s
Now we want to find the time you will take to travel 121 meters using
the speed ramp
Time = Distance ÷ speed
Distance = 121 meters
Speed 3.75 m/s
Time = 121 ÷ 3.75 = 32.27 seconds
It takes you 32.27 seconds to travel 121 m using the speed ramp
