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Inga [223]
3 years ago
10

A swimmer can swim at a velocity v in still water. She swims upstream a distance d against the current, which has a velocity u.

She then swims back to her starting point. A) how long does it take her to make the round-trip? B) what is her average speed for the trip? C) for what value of u u is her average speed the greatest?
Physics
1 answer:
xxTIMURxx [149]3 years ago
4 0
Upstream speed: v - u
Downstream speed: v + u
Total distance: 2d

A) total time = d / (v - u)  + d / (v + u)

B) Average speed = total distance / total time
V(av) = 2d / [ d / (v -  u) + d / (v + u) ]
V(av) = 2d / [d(v + u + v - u) / (v - u)(v + u) ]
V(av) = (v² - u²) / v

C) If u is 0, her average speed will be the greatest, equal to v
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Marianna [84]

Distance of fall from rest,
without air resistance              =  (1/2) (gravity) (time)²

                                             = (1/2) (9.8 m/s²) (95 sec)²

                                             =  (4.9 m/s²) (9,025 sec²)

                                             =        44,222.5 meters  .

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6 0
3 years ago
1) A force of 20 Newton acts on a bar having a cross sectional area of 0.8m^2 and length 10cm.calculate the stress developed in
Elanso [62]

Answer:25N/M^2

Explanation:

Force=20N Area=0.8M^2

Stress=force/area

Stress=20/0.8

Stress=25N/M^2

4 0
3 years ago
As stars age and become larger they become ________ and ________
sleet_krkn [62]
They become old and explode.
5 0
3 years ago
If the distance d (in meters) traveled by an object in time t (in seconds) is given by the formula d = A + Bt^2, the SI units of
Yuliya22 [10]

Answer:

The SI units of the “A” is m (meters)

The SI units of the “B” is m/s^2

Explanation:

Given the distance = d meters.

Time taken to travel = t (seconds)

Function of the distance, d = A + Bt^2

Now we have given the above information and from the given distance function, we have to find the SI units of the A and B. Here, below are the SI units.

Thus, the SI units of the “A” is = m (meters)

The SI units of the “B” is = m/s^2

6 0
3 years ago
Example of nuclear fission and nuclear fusion​
EleoNora [17]

Answer:

In fission, energy is gained by splitting apart heavy atoms, for example uranium, into smaller atoms such as iodine, caesium, strontium, xenon and barium, to name just a few. However, fusion is combining light atoms, for example two hydrogen isotopes, deuterium and tritium, to form the heavier helium.

Explanation:

I hope this helped you

(Sorry If it didn't)

4 0
3 years ago
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