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3 years ago

6

How can an object have high speed, but a low (or zero) velocity.

1 answer:

Ne4ueva [31]3 years ago

6 0

Something that goes round in circles could have a high speed but zero average velocity.

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Which of the following best describes seamounts and islands of the deep ocean basins?

Rina8888 [55]

Answer: The correct option is (d)

lava flows built up from the ocean floor by multiple, summit and flank eruptions

Explanation:

Piles of baseltic lava flows built up from the ocean floor by multiple summit and flank eruptions describes seamounts and islands of the deep ocean basins.

4 0

4 years ago

Under what conditions will a moving 0.030 kg marble and a moving 2.43 kg rock have the same kinetic energy

Anestetic [448]

Answer:

To have the same kinetic energy the speed of the marble must be 9 times the speed of rock.

Explanation:

The general formula of kinetic energy is given as follows:

$K.E = \frac{1}{2}mv^{2}$

where,

K.E = Kinetic Energy

m = mass of the object

v = speed of the object

So, for the marble and rock to have same kinetic energy, we can write:

$K.E_{marble} = K.E_{rock}\\\\\frac{1}{2}m_{marble}v_{marble}^{2} = \frac{1}{2}m_{rock}v_{rock}^{2}\\\\(0.03\ kg)v_{marble}^{2} = (2.43\ kg)v_{rock}^{2}\\\\taking\ square\ root\ on\ both\ sides:\\v_{marble} = \sqrt{\frac{2.43\ kg}{0.03\ kg}}v_{rock}\\\\v_{marble} = 9\ v_{rock}$

<u>Hence, to have the same kinetic energy the speed of the marble must be 9 times the speed of rock.</u>

4 0

3 years ago

If the frequency of wave is 400 Hz and its

agasfer [191]

Answer:

D) 1000 m/s

Explanation:

$wavelength = \frac{velocity}{frequency}$

You have the wavelength and frequency, you just need to solve for velocity. You can do this by multiplying each side of the equation by frequency.

Hope this helps.

8 0

4 years ago

5) Find the initial velocity for a 700 kg car that

Serhud [2]

Answer:

Δv = 12 m/s, but we are not given the direction, so there are really an infinite number of potential solutions.

Maximum initial speed is 40.6 m/s

Minimum initial speed is 16.6 m/s

Explanation:

Assume this is a NET impulse so we can ignore friction.

An impulse results in a change of momentum

The impulse applied was

p = Ft = 1400(6.0) = 8400 N•s

p = mΔv

Δv = 8400 / 700 = 12 m/s

If the impulse was applied in the direction the car was already moving, the initial velocity was

vi = 28.6 - 12 = 16.6 m/s

if the impulse was applied in the direction opposite of the original velocity, the initial velocity was

vi = 28.6 + 12 = 40.6 m/s

Other angles of Net force would result in various initial velocities.

5 0

3 years ago

If the specific surface energy for magnesium oxide is 1.0 J/m2 and its modulus of elasticity is (225 GPa), compute the critical

alexdok [17]

Answer:

The critical stress required for the propagation of an initial crack $\sigma_{c}$ = 21.84 M pa

Explanation:

Given data

Modulus of elasticity E = 225 × $10^{9}$ $\frac{N}{m^{2} }$

Specific surface energy for magnesium oxide is $\gamma_{s}$ = 1 $\frac{J}{m^{2} }$

Crack length (a) = 0.3 mm = 0.0003 m

Critical stress is given by $\sigma_{c}^{2} }$ = $\frac{2 E \gamma}{\pi a}$ -------- (1)

⇒ 2 E $\gamma_{s}$ = 2 × 225 × $10^{9}$ × 1 = 450 × $10^{9}$

⇒ $\pi$ a = 3.14 × 0.0003 = 0.000942

⇒ Put these values in equation 1 we get

⇒ $\sigma_{c}^{2} }$ = $\frac{450 }{0.000942} 10^{9}$

⇒ $\sigma_{c}^{2} }$ = 4.77 × $10^{14}$

⇒ $\sigma_{c}$ = 2.184 × $10^{7}$ $\frac{N}{m^{2} }$

⇒ $\sigma_{c}$ = 21.84 $\frac{N}{mm^{2} }$

⇒ $\sigma_{c}$ = 21.84 M pa

This is the critical stress required for the propagation of an initial crack.

4 0

3 years ago