Answer:
20 mins
Explanation:
To go 90 km it takes =60 mins(1 hr)
" " 1 km it takes =60/90 mins
" " 30 km it takes =60/90 multiplied by 30
= 20 mins
Answer:
The correct answer is option A: they are isotopes.
Explanation:
From atom X we know that the number of protons is 7 and the number of neutrons is 7 and from atom Z we know that the number of protons is 7 and the number of neutrons is 8.
Since the number of protons of atom X and atom Z is the same, we have that atom X and atom Z is the same element. The difference in the number of neutrons tells us that atom X and atom Z are isotopes. Remember that an isotope is one element that has atoms with different numbers of neutrons.
The mass number is given by:
Where <em>n</em> is the number of neutrons and <em>p </em>is the number of protons.
For atom X and atom Z we have:

Hence, they have a different mass number.
We know that the element with 7 protons is nitrogen. The first isotope is
and the second isotope is
. Both isotopes are stables (they are not radioactive).
Therefore, the correct answer is option A: they are isotopes.
I hope it helps you!
Answer:he conducts the investigation to see the effect acidic water has on limestone
Explanation:
One of the major limitations of using the ball and stick model for DNA, is that within a single double stranded segment of DNA, one would have to use many many balls to represent atoms that are present in the sugar phosphate backbone, along with all of the main atoms that compose the nitrogenous bases of DNA, we also cannot construct or show the helical form of DNA, by using balls and sticks as well.
Answer:
The kinetic energy of the particle will be 12U₀
Explanation:
Given that,
A particle is launched from point B with an initial velocity and reaches point A having gained U₀ joules of kinetic energy.
Constant force = 12F
According to question,
The kinetic energy is
....(I)
Constant force = 12F
A resistive force field is now set up ,
Resistive force is given by,

When the particle moves from point B to point A then,
We need to calculate the kinetic energy
Using formula for kinetic energy

Put the value of 

Now, from equation (I)

Hence, The kinetic energy of the particle will be 12U₀.