Answer:
The electro magnesium of the atoms cause the magnetic force to charge thus creating electricity. just kidding
Explanation:
If you read on the second paragraph it states that magnesium charged created electricity.
Answer:
12 km/h
Explanation:
Average Speed = Distance / Time (or rate)
Pick a point on the graph for Ian and plug in values.
For example, 20 minutes -> 4km
Hence, Average speed = 4km ÷ 20 minutes = 0.2 km/min
0.2 km/min × 60 = 12 km/h
Answer:
changing the polarity or direction of the battery changes the sign of the voltage and the current
Explanation:
The sign of current and voltage are due to established conventions.
The way that a DC circuit with negative current values is by changing the polarity of the power source or by inverting the battery, this creates that the electrons move in the opposite direction
Changing the battery also changes the direction of the power difference, since the potential from positive to negative, in most cases negative is assigned a potential of zero volts
In summary, changing the polarity or direction of the battery changes the sign of the voltage and the current
Answer:
1977.696 J
Explanation:
Given;
Weight of the box = 28.0 kg
Force applied by the boy = 230 N
angle between the horizontal and the force = 35°
Therefore,
the horizontal component of the force = 230 × cosθ
= 230 × cos 35°
= 188.405 N
Coefficient of kinetic friction, μ = 0.24
Force by friction, f = μN
here,
N = Normal force = Mass × acceleration due to gravity
or
N = 28 × 9.81 = 274.68 N
therefore,
f = 0.24 × 274.68
or
f = 65.9232 N
Now,
work done by the boy, W₁ = 188.405 N × Displacement
= 188.405 N × 30
= 5652.15 J
and,
the
work done by the friction, W₂ = - 65.9232 N × Displacement
= - 65.9232 N × 30 m
= - 1977.696 J
[ since the friction force acts opposite to the direction of motion, therefore the workdone will be negative]