In most cases the temperature must increase for thermal expansion to occur. Most substances expand as temperature increases because the atoms or molecules vibrate faster as temperature increases and experience greater separation.
Answer:
a = 0.7267
, acceleration is positive therefore the speed is increasing
Explanation:
The definition of acceleration is
a = dv / dt
they give us the function of speed
v = - (t-1) sin (t² / 2)
a = - sin (t²/2) - (t-1) cos (t²/2) 2t / 2
a = - sin (t²/2) - t (t-1) cos (t²/2)
the acceleration for t = 4 s
a = - sin (4²/2) - 4 (4-1) cos (4²/2)
a = -sin 8 - 12 cos 8
remember that the angles are in radians
a = 0.7267
the problem does not indicate the units, but to be correct they must be m/s²
We see that the acceleration is positive therefore the speed is increasing
Answer: When electricity flows through it.
Explanation:
The electromagnet exhibits magnetic properties only as soon as current flows through the nucleus. Namely, the electric current in the space around the electrical conductor through which it passes creates a magnetic field. Unlike a permanent magnet, which has a permanent property of magnetism, the electromagnet is a temporary magnet because the magnetic field also disappears when the current ceases.
Answer:
840000 J/min
Explanation:
Area = A = 0.1 m²
Bottom of pot temperature = 200 °C
Thermal conductivity = k = 14 J/sm°C
Thickness = L = 1 cm = 0.01 m
Temperature of boiling water = 100 °C
From the law of heat conduction
Q = kAΔT/L
⇒ Q = 14×0.1×(200-100)/0.01
⇒ Q = 14000 J/s
Converting to J/minute
Q = 14000×60 = 840000 J/min
∴ Heat being conducted through the pot is 840000 J/min
W=F*D
83J=F*14
83/14=F
5.92N