1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
leonid [27]
3 years ago
5

Which of the following include exact numbers? a) The speed of light in a vacuum is a physical constant; to the nearest m/s, it i

s2.99792 ×108 m/s. b) The density of mercury at 25°C is 13.53 g/mL. c) There are 3600 s in 1h. d) In 2003, the United States had 50 states.
Physics
1 answer:
telo118 [61]3 years ago
3 0

Answer:

Explanation:

Exact numbers are those numbers which are known with 100% certainty  or accuracy . Numbers having decimal are generally not exact because they are a part of long drawn decimal number after rounding off  to certain places after decimal.

On the basis of this definition we can say as follows

speed of light is 2.99792 ×108 . Here the number quoted is not an exact number because it is a rounded off figure of speed of light to five digits  after decimal .

Similarly density of mercury too is rounded off to two digits after decimal

so it is also not a exact number.

There are 3600 s in 1 h . Here 3600 s is  an  exact number because one hour has been defined as 3600 s . It is not measured by any instrument.

In 2003, the United States had 50 states. Here 50 is an exact number .  

You might be interested in
If an astronaut weighs 900 n on earth, what does he weigh on the planet venus?
Ber [7]
Use w=m*g value of g is 1.67m/s^2
5 0
3 years ago
Someone please help me with these questions! (The ones in the picture) Please I am super confused!
lozanna [386]

Answer:

c-d

Explanation:

3 0
3 years ago
Which of the following is a type of T cell?
Bess [88]

Answer:

D

Explanation:

7 0
3 years ago
Read 2 more answers
Choose either eclipses or lunar phases and make a model of the event. Your model can take any form, providing it can explain how
babymother [125]

Answer: See the explanation below.

Explanation: For this assignment, I chose to display how eclipses are created.

My model was made utilizing a 3D displaying device program for all intents and purposes. The items utilized are three models I made for this presentation, Earth, the moon, and the sun. These three models will be utilized for the showcase.  

The light that shines from the sun would create a shadow on the moon. The moon would then catch the light that should've arrived on Earth, making the shadow we call an eclipse. Earth gets a shadow of the moon and the remainder of Earth is lit up from the rest of the light, making an eclipse.  

The individual I demonstrated my project to was [<em>Someone you know</em>], [<em>Pronoun</em>] said it precisely took after the occasion of an eclipse. The light from the sun being shined on to the moon rather than the Earth, creating the shadow we call an eclipse.

5 0
3 years ago
Strontium−90 is one of the products of the fission of uranium−235. This strontium isotope is radioactive, with a half-life of 28
Ludmilka [50]

Answer : The time passed in years is 20.7 years.

Explanation :

Half-life = 28.1 years

First we have to calculate the rate constant, we use the formula :

k=\frac{0.693}{t_{1/2}}

k=\frac{0.693}{28.1\text{ years}}

k=2.47\times 10^{-2}\text{ years}^{-1}

Now we have to calculate the time passed.

Expression for rate law for first order kinetics is given by:

t=\frac{2.303}{k}\log\frac{a}{a-x}

where,

k = rate constant  = 2.47\times 10^{-2}\text{ years}^{-1}

t = time passed by the sample  = ?

a = initial amount of the reactant  = 1.00 g

a - x = amount left after decay process = 0.600 g

Now put all the given values in above equation, we get

t=\frac{2.303}{2.47\times 10^{-2}}\log\frac{1.00}{0.600}

t=20.7\text{ years}

Therefore, the time passed in years is 20.7 years.

8 0
3 years ago
Other questions:
  • Find the kinetic of a 0.1 kilogram toy truck moving at a speed of 1.1 meters per second
    8·1 answer
  • The kinetic energy of a car of mass 180kg moving at a constant velocity is 4410J. What is its velocity?
    14·1 answer
  • A circular wire loop has a radius of 7.50 cm. a sinusoidal electromagnetic plane wave traveling in air passes throughthe loop, w
    7·2 answers
  • What happens to the size of the image as the focal length is increased?
    10·1 answer
  • Find the average velocity of the object from point B to C.
    13·1 answer
  • A 0.203-kg plastic ball moves with a velocity of 0.30 m/s. it collides with a second plastic ball of mass 0.092 kg, which is mov
    13·1 answer
  • Elias stretches a rubber band and let's it go. The rubber band flies across the room. Elias says this demonstrates the transform
    11·1 answer
  • For the circuit, suppose C=10µF, R1=1000Ω, R2=3000Ω, R3=4000Ω and ls=1mA. The switch closes at t=0s.1) What is the value of Vc (
    11·1 answer
  • Write short note on fulcrum​
    12·1 answer
  • Can someone plz help me :'(
    7·2 answers
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!