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3 years ago

A stone tumbles into a mine shaft strikes bottom after falling for 4.2 seconds. How deep is the mine shaft

1 answer:

3 0

$d = u \times t \: + \frac{1}{2} \times a \times {t}^{2}$
Since initial velocity is zero hence , u = 0

=> d = 1/2 * a * t2

$d = 0.5 \times 9.8 \times {4.2}^{2}$
on solving we get

d = 86.436 metres

Note ; Here Gravitational Acceleration is take as , g = 9.8 m/s2

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Explain in your own words how volume is measured.

pav-90 [236]

Answer:

volume measured by pid^3 over 6 i think

Explanation:

7 0

3 years ago

Read 2 more answers

Find the total electric charge of 1.7 kg of electrons. me=9.11×10−31kg, e=1.60×10−19C.

Gelneren [198K]

Answer:

$2.99\cdot 10^{11}C$

Explanation:

The mass of one electron is

$m_e = 9.11\cdot 10^{-31}kg$

So the number of electrons contained in M=1.7 kg of mass is

$N=\frac{M}{m_e}=\frac{1.7 kg}{9.11\cdot 10^{-31}kg}=1.87\cdot 10^{30}$

The charge of one electron is

$e=1.60\cdot 10^{-19} C$

So, the total charge of these electrons is equal to the charge of one electron times the number of electrons:

$Q=Ne=(1.87\cdot 10^{30})(1.6\cdot 10^{-19}C)=2.99\cdot 10^{11}C$

8 0

2 years ago

A wave pulse traveling to the right along a thin cord reaches a discontinuity where the rope becomes thicker and heavier. What i

Talja [164]

Answer:

the reflected wave is inverted and the transmitted wave is up

Explanation:

To answer this question we must analyze the physical phenomenon, with an wave reaching a discontinuity, we can analyze it as a shock.

Let's start when the discontinuity is with a fixed, very heavy and rigid obstacle, in this case the reflected wave is inverted, since the contact point cannot move

In the event that it collides with an object that can move, the reflected wave is not inverted, this is because the point can rise, they form a maximum at this point.

In the proposed case the shock is when the thickness changes, in this case we have the above phenomena, a part of the wave is reflected by being inverted and a part of the wave is transmitted without inverting.

The amplitude sum of the amplitudes of the two waves is proportional to the lanería that is distributed between them.

When checking the answers the correct one is the reflected wave is inverted and the transmitted wave is up

8 0

3 years ago

Read 2 more answers

An object has a mass of 30 grams and measures 3cmx2cmx1cm. What is the density of the object?

dimulka [17.4K]

The density of the object is the ratio of its mass and volume. From the given dimensions above, we determine the volume through the equation,

V = L x W x H

Substituting,

V = (3 cm)(2 cm)(1 cm) = 6 cm³

From the idea presented above,
d = m/V

Substituting the known values,

d = (30 g)/ (6 cm³) = 5 g/cm³

ANSWER: 5 g/cm³

4 0

3 years ago

On a straight, level, two-lane road, two cars moving in opposite directions approach and pass each other. Car A is in the eastbo

ludmilkaskok [199]

Answer:

a) 42 m/s, positive direction (to the east), b) 42 m/s, negative direction (to the west).

Explanation:

a) Let consider that Car A is moving at positive direction. Then, the relative velocity of Car A as seen by the driver of Car B is:

$\vec v_{A/B} = \vec v_{A} - \vec v_{B}\\\vec v_{A/B} = 11 \frac{m}{s} \cdot i + 31 \frac{m}{s} \cdot i\\\vec v_{A/B} = 42 \frac{m}{s} \cdot i$

42 m/s, positive direction (to the east).

b) The relative velocity of Car B as seen by the drive of Car A is:

$\vec v_{B/A} = \vec v_{B} - \vec v_{A}\\\vec v_{B/A} = -31 \frac{m}{s} \cdot i - 11 \frac{m}{s} \cdot i\\\vec v_{B/A} = - 42 \frac{m}{s} \cdot i$

42 m/s, negative direction (to the west).

5 0

3 years ago