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givi [52]
3 years ago
8

Using energy considerations, calculate the average force a 60.0-kg sprinter exerts backward on the track to accelerate from 2.00

to 8.00 m/s in a distance of 25.0 m, if he encounters a headwind that exerts an average force of 30.0 N against him.
Physics
1 answer:
baherus [9]3 years ago
7 0

Answer:

F = 102 N

Explanation:

ASSUMING the track is horizontal to avoid gravity potential energy considerations.

The work of the applied force must overcome friction work and increase the kinetic energy of the runner

F(d) = Ff(d) + ½m(v² - u²)

F = Ff + m(v² - u²) / 2d

F = 30.0 + 60.0(8.00² - 2.00²) / (2(25.0))

F = 102 N

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Three forces act on an object. a 3 n force acts due east and a 8 n force acts due north. if the net force on the object is zero,
Bingel [31]

The third force C is in the opposite direction of the sum of the first two forces, A+B, but the magnitude is the same as A+B  

Since A & B are at right angles we can just use Pythagoras and trig:  

A+B magnitude = sqrt(6^2 + 3^2) = 6.71  

A+B angle = arctan(6/3) deg north of east = 63.4 deg (first quadrant)

So C magnitude = 6.71 (same as A+B)  

[C angle = 63.4 deg south of west (third quadrant) = -180+63.4 deg polar = -116.6 deg

6 0
3 years ago
A fixed 15.3-cm-diameter wire coil is perpendicular to a magnetic field 0.77 T pointing up. In 0.20 s , the field is changed to
maksim [4K]

Answer:

Induced emf will be 0.468 volt

Explanation:

We have given diameter of wire d = 15.3 cm

So radius r=\frac{d}{2}=\frac{15.3}{2}=7.65cm

So area A=\pi r^2=3.14\times (7.65)^2=183.76\times 10^{-4}m^2

Change in magnetic field dB = 0.26 - 0.77 = -0.51 T

Time for change in magnetic field dt = 0.26 sec

We know that emf is given by e=\frac{-d\Phi }{dt}=-A\frac{dB}{dt}=-183.76\times 10^{-4}\times \frac{-0.51}{0.2}=0.0468volt

5 0
3 years ago
Will mark as brainlist for only correct answer
Crank

Answer:

low, low

Explanation:

Longer wavelengths will have lower frequencies, and shorter wavelengths will have higher frequencies.

Large amplitude waves contain more energy. The other is frequency, which is the number of waves that pass by each second. If more waves( or more wiggly lines)  pass by, more energy is transferred each second

4 0
2 years ago
3
Nikitich [7]

Answer:

Protons and Neutrons are found in the nucleus and the electrons are found on the outside of the nucleus

Explanation:

Hope this helps

7 0
3 years ago
Select all the correct answers.
sdas [7]
I believe there are two correct answers, and those answers are A and D
5 0
3 years ago
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