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3 years ago

A ball is dropped from the top of a building. It initially

Physics

1 answer:

AysviL [449]3 years ago

8 0

Answer:

Explanation:

I'm assuming you missed the decimal point in the initial velocity and that it should be 4.0 m/s. If after a half of a second it is moving a tiny bit slower, it would be because of air resistance. You can only neglect air resistance if the problems you are doing tell you neglect it.

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Sally and Suzy are moving into their first college dorm together. They are loading all their furniture onto a truck with a ramp

Ksenya-84 [330]

Answer:

Explanation:

Formula

Mechanical advantage = length of the ramp / height

Givens

Length of the ramp = 8

Mechanical advantage = 2

height = ?

Solution

2 = 8feet / height Multiply both sides by height

2* height = 8 feet * height / height Combine

2* height = 8 feet Divide by 2

2*height/2 = 8 feet/2

height = 4 feet.

6 0

3 years ago

Which of the following best describes this image?

katrin [286]

Answer:

high accuracy low precision.

Explanation:

7 0

3 years ago

An earthquake produces longitudinal P waves that travel outward at 8000 m/s and transverse S waves that move at 4500 m/s. A seis

vivado [14]

Answer:

1234285.7 m or 1234.3 km

Explanation:

Let the distance be $d$ , the time taken by P waves be $t_P$ and the time taken by the S waves be $t_S$ .

$\text{Velocity}\dfrac{\text{Distance}}{\text{Time}}$

$\text{Time}\dfrac{\text{Distance}}{\text{Velocity}}$

For the P waves,

$t_P=\dfrac{d}{8000}$

$d=8000t_P$

For the S waves,

$t_S=\dfrac{d}{4500}$

$d=4500t_S$

Equating the $d$ ,

$8000t_P=4500t_S$

Divide both sides of the equation by 500 to reduce the terms.

$16t_P=9t_S$

Since S waves arrive 2 minutes (= 120 seconds) after P waves,

$t_S-t_P=120$

$t_S=120+t_P$

Substitute this in the equation of the distance.

$16t_P=9(t_P+120)$

$16t_P=9t_P+1080$

$7t_P=1080$

$t_P=\dfrac{1080}{7}$

Substitute this in the equation for $d$ involving $t_P$ .

$d=8000t_P$

$d=8000\times\dfrac{1080}{7}$

$d=1234285.7 \text{ m }= 1234.3 \text{ km}$

4 0

3 years ago

Water at 20 C flows through a 5-cm-diameter pipe that has a 180 vertical bend, as in Fig. P3.43. The total length of pipe betwee

Nataliya [291]

Answer:

F = 749 [N]

Explanation:

We must give full information on this problem, as well as the question that needs to be resolved.

Water at 20°C flows through a 5-cm-diameter pipe that has a 180° vertical bend. The total length of pipe between flanges 1 and 2 is 75 cm. When the weight flow rate is 230 N/s,

P1=165kPa

and

P2=134kPa

Neglecting pipe weight, determine the total force that the flanges must withstand for this flow.

We must make a U-shaped body diagram of the pipe in order to visualize the forces acting according to the pressures and the area of the pipe.

Then by means of the second law of motion of Newton, which says that the sum of the forces must be equal to the product of mass times acceleration, we can find the force Fp

Let us remember that pressure is defined as the divided force over the area, therefore:

F = P *A

where:

P = pressure

A = area

The product of the mass by acceleration, is equal to the product of the speed of the fluid by the mass flow, since we know the weight of the fluid we can find its mass flow.

$W_{flow}=230[N/s]\\W_{flow} =g*m_{flow}\\m_{flow} = W_{flow} / g\\m_{flow} = 230/9.81\\m_{flow}= 23.45[kg/s]$

In the function of the mass flow, we can find the velocity of the fluid, as we also know the diameter of the pipe

$m_{flow} = density*v*A\\where\\density = 1000[kg/m^{3}]\\ v= velocity[m/s]\\A = area [m^{2}]\\v=\frac{m_{flow}}{density*A} \\v=\frac{23.45}{1000*\frac{\pi}{4}*(5*10^{-2})^{2} } \\v= 11.94 [m/s]$