Answer: 2.9 
Explanation:
from the question we are given the following:
mass of rock = 220 g
volume of displaced water = 75 
the density of an object is gotten from the formula density = 
From the question, we were given the mass of a rock and volume of water the rock displaces.
When water is placed in a graduated cylinder and a rock is placed in the water, the volume of water the rock displaces is the increase in the reading of water after the rock has been put in it. The amount of water displaced is known as the volume of the rock.
therefore volume of the rock = volume of water displaced
density =
= 2.9 
The magnetic field is

what is magnetic field?
Magnetic field is defined as the relationship between the permittivity of free space,the magnitude of electric current,and distance.
Here is the formula,

here,
B= magnitude of the magnetic field
l= magnitude of electric current
R=distance
µ0=permittivity of free space
Now,using above formula we can calculate the magnetic field



Thus,the magnetic field is

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Answer:
r = 0.86
Explanation:
Correlation coefficients are the strength of the relationship between two variables.
Correlations can indicate anywhere between
- 1 - for a strong positive relationship.
- -1 - for a strong negative relationship.
- 0 - for no relationship at all.
Looking at sample correlation coefficient formula which says
=
÷ (
×
)
where
and
are the sample deviations and
is the sample covariance, all of which will remain the same for Maria and John.
Hence, John's correlation will be approximately 0.86 since he would have approximately the same measurement as Maria's measurement when Maria's measurement is converted from centimeters to inches.
0.67s
Explanation:
Given parameters:
Speed of bullet = 600m/s
Distance of target = 400m
Unknown:
Time taken for bullet to reach target = ?
Solution:
Speed is a physical quantity that expresses the rate of change of distance with time;
Speed = 
Since time is unknown, we make it the subject of the expression;
time =
= 
time = 0.67s
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