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3 years ago

A term used to describe water that is safe to drink?

1 answer:

8 0

The Safe Drinking Water Act (SDWA) is the federal law that protects public drinking water supplies throughout the nation. Under the SDWA, EPA sets standards for drinking water quality and with its partners implements various technical and financial programs to ensure drinking water safety.

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The spherical side mirror on a car is convex and has a radius of curvature of 25 cm. Another car is following, 20 m behind the m

svlad2 [7]

Answer:

(D) 0.99 cm

Explanation:

Given that the radius of curvature of the mirror is 25 cm.

And another car is following which is behind the mirror of 20 m.

$u=20m=2000cm$

Focal length is half of the radius of curvature and it is negative for convex lens.

Now the mirror formula.

$1/v+1/u=1/f$

So,

$1/v+1/2000=-1/(25/2)\\1/v=-1/2000-1/12.5\\v=-12.422cm$

Now

Magnification is,

$m=-v/u$

So,

$m=12.422/2000=0.00621$

So, Height of the image

$mh=0.00621\times 1.6 m\\mh=0.0099m\\mh=0.99cm$

Therefore, the image height is 0.99 cm.

4 0

4 years ago

The bodies of many cars are designed to compress or crumple during an accident. Why are cars built with a crumple zone?

Kryger [21]

By collapsing and crumpling, the force and energy is absorbed by the crumple zone and it is not transferred to the passengers inside. This is a safety feature for the passengers.

8 0

3 years ago

At the same instant that a 0.50-kg ball is dropped from 25 m above Earth, a second ball, with a mass of 0.25 kg, is thrown strai

zhannawk [14.2K]

Answer:

The center of mass of the two-ball system is 7.05 m above ground.

Explanation:

Motion of 0.50 kg ball:

Initial speed, u = 0 m/s

Time = 2 s

Acceleration = 9.81 m/s²

Initial height = 25 m

Substituting in equation s = ut + 0.5 at²

s = 0 x 2 + 0.5 x 9.81 x 2² = 19.62 m

Height above ground = 25 - 19.62 = 5.38 m

Motion of 0.25 kg ball:

Initial speed, u = 15 m/s

Time = 2 s

Acceleration = -9.81 m/s²

Substituting in equation s = ut + 0.5 at²

s = 15 x 2 - 0.5 x 9.81 x 2² = 10.38 m

Height above ground = 10.38 m

We have equation for center of gravity

$\bar{x}=\frac{m_1x_1+m_2x_2}{m_1+m_2}$

m₁ = 0.50 kg

x₁ = 5.38 m

m₂ = 0.25 kg

x₂ = 10.38 m

Substituting

$\bar{x}=\frac{0.50\times 5.38+0.25\times 10.38}{0.50+0.25}=7.05m$

The center of mass of the two-ball system is 7.05 m above ground.

8 0

3 years ago

A constant force of 11.8 N in the positive x direction acts on a 4.7-kg object as it moves from the origin to the point (1.6i –

zhenek [66]

Answer:

W = 18.88 J

Explanation:

Given that,

Constant force, F = 11.8 N (in +x direction)

Mass of an object, m = 4.7 kg

The object moves from the origin to the point (1.6i – 4.6j) m

We need to find the work is done by the given force during this displacement. The work done by an object is given by the formula as follows :

$W=F{\cdot} d\\\\W=(11.8i){\cdot} (1.6i-4.6j)\\\\=11.8\times 1.6\\\\=18.88\ J$

So, the work done by the given force is 18.88 J.

5 0

3 years ago

An object releasing energy is evidence of which type of chemical change?

Ray Of Light [21]

Exothermic is the answer to your question

8 0

3 years ago