<span>Make the surfaces smoother. Rough surfaces produce more friction and smooth surfaces reduce friction. ...Lubrication is another way to make a surface smoother. ...Make the object more streamlined. ...Reduce the forces acting on the surfaces. ...<span>Reduce the contact between the surfaces.
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Answer:
<h2>2540.16 J</h2>
Explanation:
The gravitational potential energy of a body can be found by using the formula
GPE = mgh
where
m is the mass
h is the height
g is the acceleration due to gravity which is 9.8 m/s²
From the question we have
GPE = 72 × 9.8 × 3.6 = 2540.16
We have the final answer as
<h3>2540.16 J</h3>
Hope this helps you
Answer:B
Explanation:
Given
First motor has three times as much as power as another
Let the power of smaller motor be P
Therefore bigger motor has power 3 P
and we know that energy 
Larger motor 
Smaller motor 
Therefore smaller motor will do same work if it takes three times the time taken by Larger motor
Answer:
1.24
Explanation:
The resistivity of copper
The resistivity of Aluminum,
The wires have same resistance per unit length.
The resistance of a wire is given by :

According to given condition,

So, the required ratio of the diameter of Aluminum to Copper wire is 1.24.
mass number of uranium 238 is sum of number of proton and neutrons in it
While atomic number is just number of protons
So total number of protons in it = 92
total number of neutrons in it = 238 - 92 = 146
mass of proton = 1.0073 amu
mass of neutron = 1.0087 amu
now for the calculation of mass of nuclei is given as


so option B is correct