All categories

3 years ago

Which of the following is a pure substance?

Physics

2 answers:

astraxan [27]3 years ago

7 0

Yes I agree that it is D as well

11Alexandr11 [23.1K]3 years ago

6 0

The answer to your question is D

You might be interested in

Evolutionary psychology is a relatively new approach to psychology that has been especially influenced by

Andrews [41]

the answer is David Buss

5 0

3 years ago

Read 2 more answers

A 64.9 kg sprinter starts a race with an acceleration of 3.89 m/s2. She keeps this acceleration for 17 m and then maintains the

xxMikexx [17]

Answer:

Time of race = 10.18 s

Explanation:

She keeps this acceleration for 17 m and then maintains the velocity for the remainder of the 100-m dash

Time to travel 17 m can be calculated

s = ut + 0.5at²

17 = 0 x t + 0.5 x 3.89 x t²

t = 2.96 s

Velocity after 2.96 seconds

v = 3.89 x 2.96 = 11.50 m/s

Remaining distance = 100 - 17 = 83 m

Time required to cover 83 m with a speed of 11.50 m/s

$t=\frac{83}{11.50}=7.22s$

Time of race = 2.96 + 7.22 = 10.18 s

3 0

3 years ago

Which answer shows a balanced nuclear equation for the alpha decay of plutonium-239

Setler [38]

Explanation:

When plutonium - 239 undergoes an alpha decay, it produces uranium - 235 in the process.

A radioactive occurs when a nuclide spontaneously disintegrates due to instability to produce lighter atoms which the release of radiation and energy.

²³⁹₉₄Pu ⇒ ²³⁵₉₂U + ⁴₂He + energy

In a nuclear reaction, the mass and atomic numbers must always remain conserved. Nuclear reactions do not obey the law of conservation of matter and mass.

The mass number are the superscript before the symbol of the nuclide

The atomic number is the subscript.

The sum of the atomic number on the left hand side equals that on the right hand side. This goes for the mass number too.

learn more:

Balanced nuclear equation brainly.com/question/10094982

#learnwithBrainly

4 0

3 years ago

True or false the law of coservation of charge states that charge is neither created nor destroyed but transferred from one obje

Hoochie [10]

True, charge can not be created or destroyed, only transferred

8 0

3 years ago

A catapult launches a test rocket vertically upward from a well, giving the rocket an initial speed of 80.6 m/s at ground level.

galina1969 [7]

Answer:

44.64 seconds

Explanation:

t = Time taken

u = Initial velocity

v = Final velocity

s = Displacement

a = Acceleration due to gravity = 9.8 m/s²

$v^2-u^2=2as\\\Rightarrow v=\sqrt{2as+u^2}\\\Rightarrow v=\sqrt{2\times 4.2\times 1180+80.6^2}\\\Rightarrow v=128.01\ m/s$

$v=u+at\\\Rightarrow 128.01=80.6+4.2t\\\Rightarrow t=\frac{128.01-80.6}{4.2}=11.29\ s$

Time taken to reach 1180 m is 11.29 seconds

$v=u+at\\\Rightarrow 0=128.01-9.8t\\\Rightarrow t=\frac{128.01}{9.8}=13.06\ s$

Time the rocket will keep going up after the engines shut off is 13.06 seconds.

$v^2-u^2=2as\\\Rightarrow s=\frac{v^2-u^2}{2a}\\\Rightarrow s=\frac{0^2-128.01^2}{2\times -9.8}\\\Rightarrow s=836.05\ m$

The distance the rocket will keep going up after the engines shut off is 836.05 m

Total distance traveled by the rocket in the upward direction is 1180+836.05 = 2016.05 m

The rocket will fall from this height

$s=ut+\frac{1}{2}at^2\\\Rightarrow 2016.05=0t+\frac{1}{2}\times 9.8\times t^2\\\Rightarrow t=\sqrt{\frac{2016.05\times 2}{9.8}}\\\Rightarrow t=20.29\ s$

Time taken by the rocket to fall from maximum height is 20.29 seconds

Time the rocket will stay in the air is 11.29+13.06+20.29 = 44.64 seconds

5 0

3 years ago