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3 years ago

An observer sees a full moon in the night sky. What will the Moon's phase be 10 days later?

1 answer:

5 0

I'm pretty sure the moon would be a crescent within the 10 day period because it takes about 28 days for the moon to go through the different stages.

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Study the motion map shown. what do the circled vectors represent?

BabaBlast [244]

Answer:

It's option d - Negative acceleration

Explanation:

Let's start by demonstrate why it's not option b - Speed : Speed is a scalar quantity so it can not be represented by a vector

Let's check that the green vectors represent velocity (velocity is a vector quantity, velocity is a direction aware, while speed is just a scalar)

Now let's show that the circled vectors are acceleration vectors:

Mathematically position X , velocity V and acceleration A are:

$\frac{dX}{dt} = V$ and $\frac{dV}{dt} = A$

Where X, V, A are vectors and $\frac{d(a)}{dt} = b$ indicates the derivate a of a time is equal to b.

So, this show that acceleration is a rate respect of time of velocity ⇒ When acceleration is positive, velocity increments, when acceleration is negative, velocity decrements.

The above explanation correspond to the motion map shown, getting demonstrated that the answer is D - Negative acceleration

3 0

3 years ago

A book is pushed with an initial horizontal velocity of 5.0 meters per second off the top of a desk. What is the initial vertica

PSYCHO15rus [73]

Answer:

The Initial vertical velocity is zero

Explanation:

Given that,

A book is pushed with an initial horizontal velocity, Vx = 5 m/s

According to projectile motion, the horizontal component of velocity i.e., in X-axis remains the same though out its path.

The vertical velocity varies i.e., the velocity towards the Y- axis.

The velocity of the falling book in its trajectory is the resultant velocity. Due to the action of gravity, it keeps on increasing with time.

The resultant velocity is given by relation

$V_{R} = \sqrt{{V_{x}^{2}} +[ {gt}]^{2} }$

where

gt = Vy - vertical velocity

g - acceleration due to gravity

t - time

Since, the initial horizontal velocity at that instant is equal to the resultant velocity.

Vx = 5 m/s

$V_{R}$ = 5 m/s

So, on substituting in the above equation

Vy = 0 m/s

Therefore, the initial vertical velocity is equal to zero

7 0

3 years ago

An electron with velocity v = 1.0 ´ 106 m/s is sent between the plates of a capacitor where the electric field is E = 500 V/m. I

oksano4ka [1.4K]

Answer:

The deviation in path is $4.39 \times 10^{-3}$

Explanation:

Given:

Velocity $v = 1 \times 10^{6}$ $\frac{m}{s}$

Electric field $E = 500$ $\frac{V}{m}$

Distance $x = 1 \times 10^{-2}$ m

Mass of electron $m = 9.1 \times 10^{-31}$ kg

Charge of electron $q = 1.6 \times 10^{-19}$ C

Time taken to travel distance,

$t = \frac{x}{v}$

$t = \frac{1 \times 10^{-2} }{1 \times 10^{6} }$

$t = 10^{-8}$ sec

Acceleration is given by,

$F = qE$

$ma = qE$

$a = \frac{qE}{m}$

$a = \frac{1.6 \times 10^{-19} \times 500}{9.1 \times 10^{-31} }$

$a = 8.77 \times 10^{13}$ $\frac{m}{s^{2} }$

For finding the distance, we use kinematics equations.

$y = vt + \frac{1}{2} at^{2}$

Where $v = 0$ because here initial velocity zero

$y = \frac{1}{2} at^{2}$

$y = \frac{1}{2} \times 8.77 \times 10^{13 } \times (10^{-2} )^{2}$

$y = 4.39 \times 10^{-3}$ m

Therefore, the deviation in path is $4.39 \times 10^{-3}$

6 0

3 years ago

Not every lightning strike produces thunder. a. Trueb.False

podryga [215]

Answer: The given statement is false.

Explanation:

Lightening is defined as steady expansion of air within and surrounding path due to the sudden increase in pressure and temperature that leads to emission of lightning.

Basically, lightning is a state of plasma in which the molecules are very rapidly striking with each other as it also contains positively charged ions and negatively charged electrons.

Lightning always leads to the production of thunder.

Therefore, we can conclude that the statement not every lightning strike produces thunder, is false.

7 0

3 years ago

A 4.7-kg solid sphere, made of metal whose density is 4000 kg/m3, hangs by a light cord. When the sphere is immersed in water, w

lara31 [8.8K]

Answer:

T = 34.54 N

Explanation:

First we find the buoyant force acting on the sphere, due to displaced water. For that purpose, we need to find the volume of water displaced by the sphere.

Volume of Water Displaced = V = (Mass of Sphere)/(Density of metal)

V = 4.7 kg/(4000 kg/m³)

V = 0.001175 m³

Now, the buoyant force is given as:

F = (Density of Water)(V)(g)

F = (1000 kg/m³)(0.001175 m³)(9.8 m/s²)

F = 11.52 N

Now, we find the weight of the sphere:

W = mg = (4.7 kg)(9.8 m/s²)

W = 46.06 N

Since, both the tension force (T) and buoyant force act in upward direction, while the weight of sphere act in downward direction. Therefore,

W = T + F

T = W - F

T = 46.06 N - 11.52 N

T = 34.54 N

4 0

3 years ago