Answer:

Explanation:
Given data
Mass m=67.0 kg
Final Speed vf=8.00 m/s
Initial Speed vi=2.00 m/s
Distance d=25.0 m
Force F=30.0 N
From work-energy theorem we know that the work done equals the change in kinetic energy
W=ΔK=Kf-Ki=1/2mvf²-1/2mvi²
And

So

and we know that the force the sprinter exerted Fsprinter the force of the headwind Fwind=30.0N
So
The true statements about magnetic fields and forces will be A,D and E.
<h3>What is a magnet?</h3>
An iron piece,alloy, or other substance with its constituent atoms arranged in such a way that it shows magnetism qualities,
The function of the magnet is attracting other iron-containing objects or aligning itself in a magnetic field.
There are two poles of the magnet;
1. North Pole.
2. South Pole.
The same poles repel each other, while the opposite poles attract each other. In a sense, south-south and north-north repel. While the north-south and the south-north attract each other.
The correct statements are;
(A). The north pole attracts the south pole of a magnet.
(D)Forces caused by magnetic fields are weaker farther from the magnet.
(E)Magnetic forces can act on an object even if the object isn't touching the magnet.
Hence, the true statements about magnetic fields and forces will be A,D and E.
To learn more about the magnet, refer to the link;
brainly.com/question/13026686
#SPJ1
Answer:

Explanation:
Given that:
The air resistance and friction = 700 N
The gravity caused force = 716 × 9.8 = 7016.8
Total force = (7016.8 + 700) N
Total force = 7716.8 N
∴




Answer:
El área de la placa es aproximadamente 5102.752 centímetros cuadrados.
Explanation:
Asumamos que el cambio dimensional como consecuencia de la temperatura es pequeña, entonces podemos estimar el área de la placa de cobre en función de la temperatura mediante la siguiente aproximación:
(1)
Donde:
- Ancho de la placa, en centímetros.
- Longitud de la placa, en centímetros.
- Coeficiente de dilatación, en
.
- Temperatura inicial, en grados Celsius.
- Temperatura final, en grados Celsius.
Si sabemos que
,
,
,
and
, entonces el área de la placa a la temperatura final:
![A_{f} = (65\,cm)\cdot (78\,cm)\cdot \left[1+\left(17\times 10^{-6}\,\frac{1}{^{\circ}C} \right)\cdot (400\,^{\circ}C-20\,^{\circ}C)\right]](https://tex.z-dn.net/?f=A_%7Bf%7D%20%3D%20%2865%5C%2Ccm%29%5Ccdot%20%2878%5C%2Ccm%29%5Ccdot%20%5Cleft%5B1%2B%5Cleft%2817%5Ctimes%2010%5E%7B-6%7D%5C%2C%5Cfrac%7B1%7D%7B%5E%7B%5Ccirc%7DC%7D%20%5Cright%29%5Ccdot%20%28400%5C%2C%5E%7B%5Ccirc%7DC-20%5C%2C%5E%7B%5Ccirc%7DC%29%5Cright%5D)

El área de la placa es aproximadamente 5102.752 centímetros cuadrados.
the answer should be 20 seconds