Ask question

Ask question

All categories

2 years ago

6

A stone of mass 0.55 kilograms is released and falls to the ground. Measurements show that the stone has a kinetic energy of 9.8

joules at the point of impact with the ground. What is the stone's velocity when it hits the ground?
a.6.3 meters/seconds
b.7.2 meters/seconds
c.8.1 meters/seconds
d.9.3 meters/seconds

2 answers:

Alex777 [14]2 years ago

6 0

Answer:

The correct answer is option a.

Explanation:

Kinetic energy is the energy of the object due to its motion.

Mass of the stone = m = 0.55 kg

Velocity of the stone = v

Kinetic energy of the stone when it hits the ground = K.E = 9.8 Joules

Kinetic energy is given as:

$K.E=\frac{1}{2}mv^2$

$9.8 J=\frac{1}{2}\times 0.55 kg\times v^2$

$v^2=\frac{9.8 J\times 2}{0.55 kg}$

$v=5.96 m/s \approx 6 m/s$

6.3 m/s the stone's velocity when it hits the ground.

6.3 m/s ≈ 6 m/s

The closest option to our answer is option a.

Lelu [443]2 years ago

5 0

Hope this helps you.

You might be interested in

Salim takes 100 g of water each in four identical containers P, Q, R and S and mixes the following in them. 5 g of salt in conta

Simora [160]

The container with chalk powder will contain the least amount of water, because it absorbs water, but the containers with honey and cocunut oil will conserve their amount of water, because they will prevent the water evaporation (especially cocunut oil because it will be on the top side of the container).

7 0

1 year ago

an underground explosion generates sound waves that travel through solid rock, then through a lake and then air. describe how th

DIA [1.3K]

Answer: sound can slow down, so when it travels through all of that it's muffled and kind of blocked. sound travels at 332 metres per second so it's hard to stop the sound

Explanation:

7 0

2 years ago

Which is an image of a scintillation counter?

dimulka [17.4K]

D is a scintillation counter.

3 0

2 years ago

Read 2 more answers

Suppose a group of volunteers is planning to build a park near a local lake. The lake is known to contain low levels of arsenic

Kisachek [45]

Answer:

A) 10.75 is the concentration of arsenic in the sample in parts per billion .

B) 7,633.66 kg the total mass of arsenic in the lake that the company have to remove.

C) It will take 1.37 years to remove all of the arsenic from the lake.

Explanation:

A) Mass of arsenic in lake water sample = 164.5 ng

The ppb is the amount of solute (in micrograms) present in kilogram of a solvent. It is also known as parts-per million.

To calculate the ppm of oxygen in sea water, we use the equation:

$\text{ppb}=\frac{\text{Mass of solute}}{\text{Mass of solution}}\times 10^9$

Both the masses are in grams.

We are given:

Mass of arsenic = 164.5 ng = $164.5\times 10^{-9} g$

$1 ng=10^{-9} g$

Volume of the sample = V = $15.3 cm^3$

Density of the lake water sample ,d= $1.00 g/cm^3$

Mass of sample = M = $d\times V=1.0 g/cm^3\times 15.3 cm^3=15.3 g$

$ppb=\frac{164.5\times 10^{-9} g}{15.3 g}\times 10^9=10.75$

10.75 is the concentration of arsenic in the sample in parts per billion.

B)

Mass of arsenic in $1 cm^3$ of lake water = $\frac{164.5\times 10^{-9} g}{15.3}=1.075\times 10^{-8} g$

Mass of arsenic in $0.710 km^3$ lake water be m.

$1 km^3=10^{15} cm^3$

Mass of arsenic in $0.710\times 10^{15} cm^3$ lake water :

$m=0.710\times 10^{15}\times 1.075\times 10^{-8} g=7,633,660.130 g$

1 g = 0.001 kg

7,633,660.130 g = 7,633,660.130 × 0.001 kg=7,633.660130 kg ≈ 7,633.66 kg

7,633.66 kg the total mass of arsenic in the lake that the company have to remove.

C)

Company claims that it takes 2.74 days to remove 41.90 kilogram of arsenic from lake water.

Days required to remove 1 kilogram of arsenic from the lake water :

$\frac{2.74}{41.90} days$

Then days required to remove 7,633.66 kg of arsenic from the lake water :

$=7,633.66\times \frac{2.74}{41.90} days=499.19 days$

1 year = 365 days

499.19 days = $\frac{499.19}{365} years = 1.367 years\approx 1.37 years$

It will take 1.37 years to remove all of the arsenic from the lake.

3 0

1 year ago

What features of this model will help Armando answer the question?

Scrat [10]

Answer:

The adjustable legs and the table of sand.

<em>Note:The question is incomplete. The complete question is given below.</em>

Using Models to Answer Questions About Systems

Armando’s class was looking at images of rivers formed by flowing water. Most of the rivers were wide and shallow, but one river was narrow and deep. Armando’s class thinks that this river is narrow and deep because:

the hill that the water flowed down was very steep, or
the sand grains that the water flowed through were very small.

Armando designed the model below to try to answer the question: Why is this river so narrow and deep?

Explanation:

The model designed by Armando will be helpful to answer the question because of the following features it possesses:

1. An adjustable leg- since one of the hypotheses put forward by the class to explain why the river was narrow and deep was that the hill that the water flowed down was very steep, the adjustable legs can be lowered or raised in order to make the slope shallower or steeper so that their hypothesis can be tested.

2. A table of sand- the table of sand serves as the streambed. By adjusting the size of the sand grains to be larger or smaller, the students will be able to to test their second hypothesis that the small size sand grains that the water flowed through was the reason for the river to be narrow and deep.

The results of their experiments will enable them to come to a conclusion.

5 0

2 years ago

Read 2 more answers