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3 years ago

7

When a brick is dropped from the roof of a house, it lands on the ground with a speed v. What will the speed at ground level be

for an identical brick dropped from a roof twice as high as the first one?

1 answer:

Nina [5.8K]3 years ago

4 0

Twice as much by the first brick

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An aluminum cylinder with a radius of 2.7 cm and a height of 67 cm is used as one leg of a workbench. The workbench pushes down

soldier1979 [14.2K]

Answer:

$1.9\times 10^{-4}$

$1.2\times 10^{-4}\ m$

Explanation:

r = Radius = 2.7 cm

F = Force = $3.2\times 10^4\ N$

A = Area = $\pi r^2$

$\sigma$ = Stress = $\frac{F}{A}$

E = Young's modulus = $7\times 10^{10}\ Pa$

$\epsilon$ = Strain

$L_0$ = Original length = 67 cm

$\Delta L$ = Change in length

Young's modulus is given by

$E=\frac{\sigma}{\epsilon}\\\Rightarrow \epsilon=\frac{\sigma}{E}\\\Rightarrow \epsilon=\frac{\frac{3.2\times 10^4}{\pi 0.027^2}}{7\times 10^{10}}\\\Rightarrow \epsilon=0.0001996=1.9\times 10^{-4}$

Strain is $1.9\times 10^{-4}$

Strain is given by

$\epsilon=\frac{\Delta L}{L_0}\\\Rightarrow \Delta L=\epsilon\times L_0\\\Rightarrow \Delta L=1.9\times 10^{-4}\times 0.67\\\Rightarrow \Delta L=0.0001273\\\Rightarrow \Delta L=1.2\times 10^{-4}\ m$

The cylinder height decreases by $1.2\times 10^{-4}\ m$

3 0

3 years ago

Gabriel is performing an experiment in which he is measuring the energy and work being done by a ball rolling down a hill.Which

Rufina [12.5K]

I think this one's B. energy and work are both measured in joules.

7 0

3 years ago

Read 2 more answers

What is the wavelength in air of red light from a helium neon laser?

Elza [17]

Answer:

632.8 nm is the wavelength (in air) of red light from a helium neon laser.

4 0

2 years ago

An electron passes location < 0.02, 0.04, -0.06 > m and 5 us later is detected at location < 0.02, 1.62,-0.79 > m (1

hram777 [196]

Answer:

(a)

Average velocity = < 0, 316000, 146000> m/s

(b) < 0, 2.844, 1.314 > m

Explanation:

r1 = < 0.02, 0.04, - 0.06 > m

r2 = < 0.02, 1.62, - 0.79 > m

time, t = 5 micro second = 5 x 10^-6 s

(a) Average velocity is defined as the ratio of total displacement to the total time taken.

Displacement = r = r2 - r1

r = < 0.02 - 0.02, 1.62 - 0.04, - 0.79 + 0.06 > m

r = < 0, 1.58, - 0.73 > m

So. Average velocity = $\frac{< 0, 1.58, - 0.73 >}{5 \times 10^{-6}}$

Average velocity = $< 0, 316000, 146000> m/s$

Average velocity = < 0, 316000, 146000> m/s

(b)

Distance = velocity x time

Here time, t = 9 micro second

d = < 0, 316000, 146000> x 9 x 10^-6 m

d = < 0, 2.844, 1.314 > m

5 0

3 years ago

What’s the answer to question 12 please

matrenka [14]

Answer:

C) amplitude

Explanation:

"The amplitude is a measure of the strength or intensity of the wave. For example, when looking at a sound wave, the amplitude will measure the loudness of the sound. The energy of the wave also varies in direct proportion to the amplitude of the wave."-Ducksters

7 0

3 years ago