D. F=ma
F is for force, and that equals two things, M for mass and A for acceleration. When mass is accelerated, it gives you force. Force equals multiplying mass and its acceleration.
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<h3>Explanation</h3>
The Stefan-Boltzmann Law gives the energy radiation <em>per unit area</em> of a black body:
where,
the total power emitted, 
the surface area of the body, 
the Stefan-Boltzmann Constant, and
the temperature of the body in degrees Kelvins.
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Keep as many significant figures in as possible. The error will be large when is raised to the power of four. Also, the real value will be much smaller than 
since the emittance of a human body is much smaller than assumed.
Hello there,
400 meters= 0.4 km
Time= Distance / speed
= 0.4 / 69
= 0.0057971014492754 hr
= 0.35 min
Hope this helps :))
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