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pychu [463]
3 years ago
10

A 40 kg rock is rolling toward a town at 4 m/s after an earthquake. Calculate the KE.

Physics
1 answer:
adelina 88 [10]3 years ago
4 0

Answer:

320 J

Explanation:

From the question,

KE = 1/2mv².................. Equation 1

Where KE = Kinetic Energy, m = mass of the rock, v = velocity of the rock

Given: m = 40 kg, v = 4m/s

Substitute these values into equation 1

KE = 1/2(40)(4²)

KE = 20×16

KE = 320 J

Hence the kinetic energy of the rock is 320 J

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Which type of device enables its users to see around corners?
Dmitriy789 [7]

Answer:

We can use optical fibers.

Explanation:

The optical fibers are the optical devices which is based on the total internal reflection.

The optical fiber has two layers, one is called core and the other is called cladding.

The refractive index of core is more than the cladding.

As a ray of light falls on the core at more than the critical angle for that pair of media(core and cladding), it suffers the total internal reflection at the interface.

5 0
3 years ago
Read 2 more answers
Find the mass. 10 points. Will give brainliest.
TiliK225 [7]

Answer:

<h2>3.94 kg</h2>

Explanation:

Given,

Force ( f ) = 30 N

Acceleration(a) = 7.6 m/s

Now, Let's find the mass of the ball

Using the Newton's second law of motion:

We get:

force \:  = mass \:  \times acceleration

plug the value

30 \:  = m \:  \times 7.6

Use the commutative property to reorder the terms

30 = 7.6 \: m

Swap the sides of the equation

7.6m = 30

Divide both sides of the equation by 7.6

\frac{7.6 \: m}{7.6}  =  \frac{30}{7.6}

Calculate

m = 3.94 \: kg

Hope this helps..

Best regards!!

7 0
3 years ago
Read 2 more answers
A straight wire of length 0.62 m carries a conventional current of 0.7 amperes. What is the magnitude of the magnetic field made
anyanavicka [17]

Answer:

Magnetic field at point having a distance of 2 cm from wire is 6.99 x 10⁻⁶ T

Explanation:

Magnetic field due to finite straight wire at a point perpendicular to the wire is given by the relation :

B=\frac{\mu_{0}I }{2\pi R }\times\frac{L}{\sqrt{L^{2}+R^{2}  } }      ......(1)

Here I is current in the wire, L is the length of the wire, R is the distance of the point from the wire and μ₀ is vacuum permeability constant.

In this problem,

Current, I = 0.7 A

Length of wire, L = 0.62 m

Distance of point from wire, R = 2 cm = 2 x 10⁻² m = 0.02 m

Vacuum permeability, μ₀ = 4π x 10⁻⁷ H/m

Substitute these values in equation (1).

B=\frac{4\pi\times10^{-7}\times  0.7 }{2\pi \times0.02 }\times\frac{0.62}{\sqrt{(0.62)^{2}+(0.02) ^{2}  } }

B = 6.99 x 10⁻⁶ T

3 0
3 years ago
Astrology, that unlikely and vague pseudoscience, makes much of the position of the planets at the moment of oneâs birth. The on
Anton [14]

Answer:

Explanation:

Gravitational force between two objects having mass m₁ and m₂ at a distance R

F = G m₁ m₂ / R²

Force between baby and father F₁ = 6.67x10⁻¹¹ x 4.1 x 120 / .18²

= 1.01 x 10⁻⁶ N

b )

Force between baby and Jupiter

F₂ = 6.67x10⁻¹¹ x 1.9x 10²⁷ x 4.1 / ( 6.29 x 10¹¹ )²

= 1.31 x 10⁻⁶  N

c )

Ratio = 1.01 / 1.31

= .77

4 0
3 years ago
Dana is on a train traveling at a speed of 20 km/h. Dana walks from the front of the train to the back of the train at a speed o
Maslowich

Answer:

16km/h

Explanation:

Vt=20km/h ---train speed

Vd=4km/h

Donas speed relative to ground is:

Vrd=Vt-Vd

Donas is moving in opposite direction of train .

Vrd=20km/h-4km/h

Vrd=16km/h

7 0
4 years ago
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