A 415-kg container of food and water is dropped from an airplane at an altitude of 300m. First, consider the situation ignoring
1 answer:
1) 7.8 s
Ignoring air resistance, the only force acting on the container is gravity. Therefore, we can use the following suvat equation for the free-fall case:
where
s = 300 m is the displacement of the container
u = 0 is the initial vertical velocity of the container, which starts from rest
a = g = 9.8 m/s^2 is the acceleration of gravity
t is the time
Here we have chosen downward as positive direction, so all quantities are positive
Solving the equation for t, we find:
2) 76.4 m/s
The speed of the container at any time t can be found by using another suvat equation:
where
v is the speed at time t
u = 0 is the initial speed
a = g = 9.8 m/s^2 is the acceleration of gravity
t is the time
Substituting t = 7.8 s, the time of flight, we can immediately find the final speed of the container, just before hitting the ground:
3) 4067 N
In this case, there is a parachute that produces a drag force acting upward.
When the container is falling at constant speed, 6 m/s down, it means that its acceleration is zero, so the net force acting on it is zero. This means that the air drag balances the weight of the container, therefore we can write:
where
F is the air drag
m is the mass of the container
g is the acceleration of gravity
Substituting m = 415 kg, we find the magnitude of the drag force:
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Answer:
82.76m
Explanation:
In order to find the distance of the steel ring to the ground, when its temperature has raised by 1°C, you first calculate the radius of the steel tube before its temperature increases.
You use the formula for the circumference of the steel ring:
(1)
C: circumference of the ring = 40000 km = 4*10^7m (you assume the circumference is the length of the steel tube)
you solve for r in the equation (1):
Next, you use the following formula to calculate the change in the length of the tube, when its temperature increases by 1°C:
(2)
L: final length of the tube = ?
Lo: initial length of the tube = 4*10^7m
ΔT = change in the temperature of the steel tube = 1°C
α: thermal coefficient expansion of steel = 13*10^-6 /°C
You replace the values of the parameters in the equation (2):
With the new length of the tube, you can calculate the radius of a ring formed with the tube. You again solve the equation (1) for r:
Finally, you compare both r and r' radius:
r' - r = 6,366,280.484m - 6,366,197.724m = 82.76m
Hence, the distance to the ring from the ground is 82.76m
Answer:
So No of slices to be consumed by each person = n = 65
Explanation:
Energy released by one slice = E1
h = 8850 m ; m = 79 kg ,η= 10.5%
We know that potential energy given as
u = m g h
u = 79 x 9.81 x 8850
we know from the defination of efficiency that, η= E(out)/E(in)
Now amount of PE has to be compensated, In our case, E(out) =u
Let n be the number of bread slices to be consumed.
n = E(in)/E1
n=64.76
So No of slices to be consumed by each person = n = 65
Answer:
35,79 meters
Explanation:
So, we got an archer, and we got a target. Lets call the distance between this two d.
Now, the archer fires the arrow, that, in a time travels the distance d with a speed
of 40 m/s and hits the target. We can see that the equation will be:
Immediately after this, the arrow produces a muffled sound, which will travel the distance d at 340 m/s in a time . Obtaining :
.
Finally, the sound reaches the archer, exactly 1 second after he fired the bow, so:
.
This equation allows us to write:
.
Plugging this relationship in the distance equation for the sound:
.
Now, we can replace d from the first equation, and obtain:
.
Now, we can just work a little bit:
.
Now, we can just plug this value into the first equation: