Heat used by electric heater :
Q = m • c • ∆T
Q = (75 kg)(4200 J/kg°C)(43°C - 15°C)
Q = 8.82 × 10⁶ J
Cost of electrical energy :
Cost = (8.82 × 10⁶ J)/(3.6 × 10⁶ J) • ($ 0.15)
Cost = $ 0.3675
Answer:
0.75 m
Explanation:
Let's call the distance between the bulb and the mirror x.
The bulb and the length of the mirror form a triangle. The mirror and the illuminated area on the floor form a trapezoid. If we extend the lines from the mirror edge to the reflected image of the bulb, we turn that trapezoid into a large triangle. This triangle and the small triangle are similar. So we can say:
x / 0.4 = (3 + x) / 2
Solving for x:
2x = 0.4 (3 + x)
2x = 1.2 + 0.4 x
1.6 x = 1.2
x = 0.75
So the bulb should located no more than 0.75 m from the mirror.
Check-call-Care if you are training to be a life guard.
A simple machine is a device for doing work that has only one part. Simple machines redirect or change the size of forces, allowing people to do work with less muscle effort and greater speed, thus making their work easier. There are six kinds of simple machines: the lever, the pulley, the wheel and axle, the inclined plane, the wedge, and the screw.
Because your hand is warm and the warmness melts the chocolate...