Given:
h = 600 m, the height of descent
t = 5 min = 5*60 = 300 s, the time of descent.
Let a = the acceleration of descent., m/s².
Let u = initial velocity of descent, m/s.
Let t = time of descent, s.
The final velocity is v = 0 m/s because the helicopter comes to rest on the ground.
Note that u, v, and a are measured as positive upward.
Then
u + at = v
(u m/s) + (a m/s²)*(t s) = 0
u = - at
u = - 300a (1)
Also,
u*t + (1/2)at² = -h
(um/s)*(t s) + (1/2)(a m/s²)*(t s)² = 600
ut + (1/2)at² = 600 (2)
From (1), obtain
-300a +(1/2)(a)(90000) = -600
44700a = -600
a = - 1.3423 x 10⁻² m/s²
From (1), obtain
u = - 300*(-1.3423 x 10⁻²) = 4.03 m/s
Answer:
The acceleration is 0.0134 m/s² downward.
The initial velocity is 4.0 m/s upward.
Tampered evidence/tampered corpse?
Given the distance traveled and time elapsed, the average speed of the train is approximately 26.944m/s.
<h3>What is the average speed of the train?</h3>
Speed is simply referred to as distance traveled per unit time.
Mathematically, Speed = Distance ÷ time.
Given the data in the question;
- Distance traveled = 221miles
- Elapsed time = 3 hours and 40 minutes
First we convert miles to meters and Hours minutes to seconds.
221 miles = ( 221 × 1609.344 )m = 355665.024 meters
3 hours and 40 minutes = ( 3×60×60)s + ( 40×60)s
= 10800s + 2400s
= 13200s
Now, determine the average speed.
Speed = Distance ÷ time
Speed = 355665.024m / 13200s
Speed = 26.944m/s
Given the distance traveled and time elapsed, the average speed of the train is approximately 26.944m/s.
Learn more about speed here: brainly.com/question/7359669
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Answer:
Aerobic physical activity is better for the cardiovascular system than it is for strength endurance, while anaerobic physical activity is better at building strength endurance than it is at increasing cardiorespiratory fitness.
Therefore true
