Dust,dirt, or metal chips can pose a potential what kind of injury risk in a shop

A hydrogen-filled balloon to be used in high altitude atmosphere studies will eventually be 100 ft in diameter. At 150,000 ft, t

mote1985 [299]

Answer:

The calculated result is 11.7 ft

Explanation:

You can apply the combined gas law, which incorporates Boyle's law, Charles's law, and Gay-Lussac's Law, because hydrogen demonstrates ideal gas behavior under these specific conditions.

$\frac{p_1 V_1}{T_1} = \frac{p_2 V_2}{T_2}$

where the subscripts indicate "p" for pressure, "V" for volume, and "T" for temperature (in Kelvin) at varying moments. Let's denote $t_1$ as the balloon at 150,000 ft so

$p_1 = 0.14 \ lb/in^2$

$V_1 = \frac{4}{3} \pi R_1^3 = 523598.77 \ ft^3$

and $T_1 = -67^\circ F = 218.15\ K$ .

Then $t_2$ represents the point at which the balloon is on the ground.

$p_2 = 14.7 \ lb/in^2$ and $T_2 = 68^\circ F = 293.15\ K$ .

Based on the first equation

$V_2 = \frac{p_1 V_1 T_2}{T_1 p_2}$ , we find

$V_2 = 6701.07 ft^3$ and consequently the radius turns out to be

$R_2 = \sqrt[3]{\frac{3 V_2}{4 \pi}} = 11.7 \ ft$ .

5 0

2 months ago

A 90-hp (shaft output) electric car is powered by an electric motor mounted in the engine compartment. If the motor has an avera

pantera1 [306]

Answer:

Heat supply rate is measured at 8.901 horsepower.

Explanation:

Energy efficiency of the electric vehicle, as per Thermodynamics ( $\eta$ ), is the proportion of translational mechanical power ( $\dot E_{out}$ ), expressed in horsepower, and electrical energy ( $\dot E_{in}$ ), also in horsepower. The heat supply rate ( $\dot E_{l}$ ), indicated in horsepower, that the motor delivers to the engine bay under full load can be determined by subtracting the translational mechanical energy from the electric energy. This is expressed as:

$\eta = \frac{\dot E_{out}}{\dot E_{in}}$ (1)

$\dot E_{l} = \dot E_{in}-\dot E_{out}$ (2)

$\dot E_{l} = \left(\frac{1}{\eta}-1\right)\cdot \dot E_{out}$ (3)

If we have the values of $\eta = 0.91$ and $\dot E_{out} = 90\,hp$ , the heat supply rate can be calculated as:

$\dot E_{l} = \left(\frac{1}{0.91}-1 \right)\cdot (90\,hp)$

$\dot E_{l} = 8.901\,hp$

The heat supply rate amounts to 8.901 horsepower.

4 0

3 months ago

A jar made of 3/16-inch-thick glass has an inside radius of 3.00 inches and a total height of 6.00 inches (including the bottom

mote1985 [299]

Response:

1. To find the volume of the glass shell (Vg), simply subtract the volume of the empty part of the jar (Ve) from the total volume of the jar (Vj):

Vg = Vj - Ve

Volume can be calculated by multiplying the base (B) with the height (h). The base of the jar is a circle, thus its area is πr^2 (where r indicates the radius).

The radius differs based on the jar's section: the inner radius for the empty part is d = 3 in, while for the total jar it includes the glass thickness a = 3 + 3/16 = 3.1875 in.

The height of the entire jar is given as h = 6 in, whereas for the empty portion, it's the total height minus the thickness of the glass h' = 6 - 0.1875 = 5.8125 in.

Now we can perform the calculations:

Vj = πa^2 • h = 191.42 in^3

Ve = πd^2 • h' = 164.26 in^3

Thus, the volume of the glass shell equals Vj - Ve, resulting in 27.16 in^3.

2. The mass of the glass jar can be determined by multiplying the density of the glass with the volume:

m = ρ • Vg

The glass density is provided in cubic feet, so we first convert it to cubic inches by dividing by 1728:

ρ = 165 lb/ft^3 / 1728 = 0.095 lb/in^3

m = 0.095 lb/in^3 • 27.16 in^3 = 2.59 lb

5. To calculate the weight and volume of the displaced water, we first need to ascertain how deep the jar sinks (H), as the volume of displaced water equals the submerged volume of the jar. The jar will descend until the gravitational force downwards equals the buoyancy force upwards. The displaced water volume is πa^2 • H, and the buoyancy is calculated as ρw • g • Vd (where ρw is the density of water, defined as 62.5 lb/ft^3 / 1728 = 0.036 lb/in^3, and Vd is the displaced water volume).

Thus, the buoyancy can be represented as:

B = ρw • g • πa^2 • H

Setting buoyancy equal to gravity:

B = m • g (where m is the mass of the jar). Therefore, we have:

ρw • g • πa^2 • H = m • g

From this, simplifying gives:

ρw • πa^2 • H = m

We can derive H:

H = m / (ρw • πa^2)

H = 2.25 inches

This indicates the jar will sink 2.25 inches into the water.

3. Calculating the volume of displaced water is straightforward. It matches the volume of the submerged jar:

Vd = πa^2 • H

Vd = 71.94 in^3

4. Lastly, to determine the weight of the displaced water:

m = ρw • Vd

m = 0.036 lb/in^3 • 71.94 in^3

m = 2.59 lb

As evident, the mass of the jar aligns with the mass of the displaced water. Following this logic could have simplified our calculations, but I chose to elaborate for clarity.

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6 0

2 months ago

___________ is NOT a common injury that an automotive tech may experience at work.

Viktor [391]

Answer: The most frequently occurring injuries were sprains/strains, accounting for 39% of the total; lacerations comprised 22%, and contusions represented 15%. Almost half (49%) of the injuries led to one or more days of lost or restricted work; 25% resulted in 7 or more days lost or restricted.

Explanation:

Sprains/strains were the predominant injuries happening, making up 39% of all cases, while lacerations followed at 22% and contusions at 15%. Of these injuries, 49% caused employees to miss or face restricted workdays, with 25% leading to a minimum of 7 days lost or restricted.

7 0

3 months ago