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Nookie1986 [14]

3 years ago

12

Samuel adds a teaspoon of salt to a glass of water. He notices that the salt disappears. Samuel takes a dip to discover that the

water tastes salty. What kind of change has occurred

1 answer:

Tpy6a [65]3 years ago

6 0

It is a chemical change because the salt is dissolving.

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An object moves in a straight path. Its position x as a function of time t is presented by the equation x(t) = at – bt2+c, where

ankoles [38]

Answer:

The answer is below

Explanation:

Given that:

x(t) = at – bt2+c

a) x(t) = at – bt2+c

Substituting a = 1.4 m/s, b = 0.06 m/s2 and c =50 m gives:

x(t) = 1.4t - 0.06t² + 50

At t = 5, x(5) = 1.4(5) - 0.06(5)² + 50 = 55.5 m

At t = 0, x(0) = 1.4(0) - 0.06(0)² + 50 = 50 m

The average velocity (v) is given as:

$v=\frac{x(5)-x(0)}{5-0}\\ \\v=\frac{55.5-50}{5-0}=1.1\\ \\v=1.1\ m/s$

b) x(t) = 1.4t - 0.06t² + 50

At t = 10, x(10) = 1.4(10) - 0.06(10)² + 50 = 58 m

At t = 0, x(0) = 1.4(0) - 0.06(0)² + 50 = 50 m

The average velocity (v) is given as:

$v=\frac{x(10)-x(0)}{10-0}\\ \\v=\frac{58-50}{10-0}=0.8\\ \\v=0.8\ m/s$

c) x(t) = 1.4t - 0.06t² + 50

At t = 15, x(5) = 1.4(15) - 0.06(15)² + 50 = 57.5 m

At t = 10, x(10) = 1.4(10) - 0.06(10)² + 50 = 58 m

The average velocity (v) is given as:

$v=\frac{x(15)-x(10)}{15-10}\\ \\v=\frac{57.5-58}{15-10}=0.1\\ \\v=0.1\ m/s$

6 0

3 years ago

3 ways pollution gets into neighborhoods

SashulF [63]

Answer:

1. Leaving trash on the ground and not picking it up.

2. Polluting the lake, if your neighborhood has one.

3. Outside people come and dump their waste to your neighborhood.

Hope this helps!

7 0

3 years ago

A rod made from insulating material carries a net charge, while a copper sphere is neutral. The rod and the sphere do not touch.

navik [9.2K]

<span>As the charged insulating rod approaches the sphere (not in contact), free electrons in the sphere move. If the rod is negatively charged, free electrons move to the side of the sphere opposite the side with the rod. If the rod is positively charged, the free electron moves to the side of the sphere with the rod. In either case, the region of the sphere near the rod acquires a charge with the sign opposite to that on the rod.

a. Since opposedly charged objects always attract each other, the rod and ball always experience mutual attractive forces.

b. Since the side of the sphere near the bar always has the opposite charge to the charge of the rod, the rod and the sphere always attract each other. <span>They do not repel each other.</span></span>

3 0

3 years ago

A wooden block of dimensions of 6 cm ⨯ 6 cm ⨯ 15 cm floats with the long axis oriented horizontally and the of the square faces

schepotkina [342]

Explanation:

(a) Formula to calculate volume of the submerged wooden block is as follows.

$V_{sub} = l \times w \times d$

It is given data of the wooden block is as follows.

depth = 7.96 cm, length (l) = 6 cm

width (w) = 4 cm,

So, we will calculate the volume of the submerged wooden block as follows.

$V_{sub} = l \times w \times d$

= $6 \times 6 \times 7.96$

= 286.56 $cm^{3}$

Hence, the submerged volume of the block is 286.56 $cm^{3}$ .

(b) Expression for the buoyant force acting on the wooden block is as follows.

$F_{B} = \rho_{w} g V_{sub}$

And, expression for the force of gravity of the wooden block is as follows.

$F_{g} = m_{b}g$

As the wooden block is floating on the water hence, buoyant force is balanced by the weight of the block.

$F_{g} = F_{B}$

Hence, mass of the wooden block will be calculated as follows.

$F_{g} = F_{B}$

$m_{b}g = \rho_{w}gV_{sub}$

$m_{b} = \rho_{w}V_{sub}$

= $997 kg/m^{3} \times 286.56 cm^{3}$

= $997 kg/m^{3} \times 286.56 \times 10^{-6} m^{3}$

= 0.02857 kg

Therefore, mass of the given block is 0.02857 kg

(c) Expression for the density of the block is as follows.

$\rho_{b} = \frac{m_{b}}{V_{b}}$

Now, expression for the total volume of the wooden block is as follows.

$V_{b} = l \times w \times h$

Hence, density of the given block is as follows.

$\rho_{b} = \frac{m_{b}}{V_{b}}$

= $\frac{m_{b}}{lwh}$

= $\frac{0.02857 kg}{4 \times 4 \times 15}$

= $1.19 \times 10^{-4} kg/cm^{3}$

Therefore, density of the given block is $1.19 \times 10^{-4} kg/cm^{3}$ .

3 0

3 years ago

a sample of oxygen gas occupies a volume of 25.0ml at 740.0 torrent what volume will occupyat 800.0 torr

melomori [17]

Answer:

23.1mL

Explanation:

Given parameters:

Initial volume of the gas = 25ml

Initial pressure = 740torr

Final pressure = 800torr

Unknown:

Final volume = ?

Solution:

To solve this problem, we apply Boyle's law which states that "the volume of a fixed mass of a gas varies inversely as the pressure changes if the temperature is constant"

P₁ V₁ = P₂ V₂

P and V are pressure and volume

1 and 2 are initial and final states

Insert the parameters and solve;

740 x 25 = 800 x v₂

v₂ = 23.1mL

6 0

3 years ago