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Lena [83]
3 years ago
15

What must be true of the direction of the current in the electromagnets of a DC motor?

Physics
2 answers:
ANEK [815]3 years ago
8 0
It needs to stay the same
inessss [21]3 years ago
7 0
It's needs to stay the same 

The correct is D.

Hope this helps!
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A ball of mass 0.3 kg is released from rest at a height of 8 m. How fast is it going when it hits the ground? (Gravity being equ
docker41 [41]

Answer:

Explanation:

Mass doesn't matter here because when something is falling, gravity plays fairly; an elephant falls at the same rate of acceleration as does a feather. What DOES matter is everything pertinent to the y-dimension of free-fall:

a = -9.8 m/s/s

v₀ = 0 (since the ball was held before it was dropped)

v = ??

Δx = -8 m (negative because the ball drops this far below the point from which it was released).

Putting all this together in one equation:

v² = v₀² + 2aΔx and filling in this equation:

v² = (0)² + 2(-9.8)(-8) and

v² = 156.8 so

v = 12.5 which rounds to 13 if you're using 2 sig figs, and rounds to 10 if you're only using 1 (which you should be, according to the way the numbers have been given in this problem)

3 0
3 years ago
1. What are electromagnetic waves?
zhuklara [117]

Answer:

Waves of energy traveling through a space

Explanation:

8 0
2 years ago
17- How much work is needed for a climber in order to climb 45 m height, where his weight is 70 kg. also, calculate the power re
Snezhnost [94]

Answer:

Work Done= 3150J

Power= 1.75W

Explanation:

Work Done= Force x the distance travelled in the direction of the force (W= f x d)

Weight is a force, i think the qn. stated it wrongly, it should be 70N not 70kg.

Work Done= 70 x 45

=3150J

Power= Work Done/Time

=3150/(30x60)

*convert minutes to seconds since the S.I. unit of Power is joules/seconds(J/s) or watts(W)

=1.75W

8 0
3 years ago
the speed of light in a vaccum is about 3.00 x10^8m/s to determine how many km a pulse from a lazer beam travels in exactly one
neonofarm [45]

Distance = (speed) x (time)

Distance = (3 x 10⁸ meter/second) x (1 hour)

Distance = 3 x 10⁸  meter-hour per second

Distance = 3 x 10⁵ kilometer-hour per second

Hmmm.  That answer is perfectly correct and totally useless.  We have no idea how far one meter-hour per second is.  It's a unit we never use.  We'd better convert the answer to a unit of length that we use every day.

(3 x 10⁵ km-hour/sec) x (3,600 sec/hour) =

(3 x 10⁵ x 3,600)  (km-hour-sec/hour-sec) =

1.08 x 10⁹ km

THAT's it !  A pulse of light in vacuum travels 1.08 billion km in one hour.

3 0
3 years ago
Which of these is most likely a step in the formation of soil? a. erosion of soil b. crystallization of rocks c. animals digging
MaRussiya [10]
The answer is C. <span>animals digging rocks</span>
4 0
3 years ago
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