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3 years ago

How do we know if something is moving?

1 answer:

5 0

An object is in motion if its distance relative to another object is changing. To tell if an object is moving, you use a reference point. If an object's distance from another object [reference point] is changing. A place or object used for comparison to determine if something is in motion.

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In a science fiction story, a microscopic black hole is given an enormous positive charge by firing an un-neutralized ion drive

Olegator [25]

Answer: distance d = 4.73e10m

Explanation: Suppose the charge on the black hole is 5740 C which is a positive charge.

Using electric potential V formula:

V = kq / d

Where K = 9.05×10^9Nm^2/C

And e = 1.6×10^-19C

But you don't need to substitute it.

1090 V = 8.99e9N·m²/C² * 5740C /d

Make d the subject of formula

d = 4.73e10 m

6 0

3 years ago

Imagine that the ball on the left is given a nonzero initial velocity in the horizontal direction, while the ball on the right c

masya89 [10]

Answer:

vₓ = xg/2y

Explanation:

In this question, let us find the time it takes for the ball on the right that has zero initial velocity to reach the ground.

By newton equation of motion we know that

y = v₀ t - ½ g t²

t = 2y / g

This is the time it takes for the ball on the right to reach the ground; at this time the ball on the left travels a distance

vₓ = x/t

vₓ = xg/2y

Where we assume that x and y are known.

7 0

3 years ago

By what percent is the torque of a motor decreased if its permanent magnets lose 6.5 % of their strength

djyliett [7]

6 is the answer I remember the answer from when I took this and it was easy

4 0

2 years ago

To maintain a constant speed, the force provided by a car's engine must equal the drag force plus the force of friction of the r

sweet [91]

Answer:

a). 53.75 N and 101.92 N

b). 381.44 N and 723.25 N

Explanation:

$V= 77 \frac{km}{h}* \frac{1h}{3600 s} *\frac{1000m}{1 km} = 21.38 \frac{m}{s} \\V=106 \frac{km}{h}* \frac{1h}{3600 s} *\frac{1000m}{1 km} = 29.44 \frac{m}{s}$

a).

ρ $= 1.2 \frac{kg}{m^{3} }$ , $A_{t}= 0.7 m^{2}$ , $D_{t}= 0.28$

$F_{t1} = \frac{1}{2} * D_{t} * A_{t}* p_{t}* v_{t}^{2}$

$F_{t1} = \frac{1}{2} * 0.28 * 0.7m^{2} * 1.2\frac{kg}{m^{3} }* 21.38^{2}= 53.75 N$

$F_{t1} = \frac{1}{2} * 0.28 * 0.7m^{2} * 1.2\frac{kg}{m^{3} }* 29.44^{2}= 101.92 N$

b).

ρ $= 1.2 \frac{kg}{m^{3} }$ , $A_{h}= 2.44 m^{2}$ , $D_{h}= 0.57$

$F_{t1} = \frac{1}{2} * D_{h} * A_{h}* p_{h}* v_{h}^{2}$

$F_{t1} = \frac{1}{2} * 0.57 * 2.44 m^{2} * 1.2\frac{kg}{m^{3} }* 21.38^{2}= 381.44 N$

$F_{t1} = \frac{1}{2} * 0.57 * 2.44 m^{2} * 1.2\frac{kg}{m^{3} }* 29.44^{2}= 723.25 N$

6 0

3 years ago

Why are ionic solids poor conductors of electricity? The lattice is brittle. The ions are neutral. The ions are of equal but opp

sveta [45]

The ions are in fixed positions.

Explanation:

Ionic solids are poor conductors of electricity because their ions are fixed in position. Their ions are not free to move about. They are fixed in crystal lattices.

For the conduction of electricity, compounds must possess free mobile electrons and moving ions in solution.
Ionic compounds are formed by the electrostatic attraction between a metallic and non-metallic ion.
They actually contain ions but their ions are locked up.
They are not free to move about.
Electrical conduction involves ion mobility.
In molten and aqueous forms, they are able to conduct electricity because their ions are then mobile.

learn more:

Ionic compound brainly.com/question/6071838

#learnwithBrainly

6 0

3 years ago