Mountaineers wear shoes called approach shoes or rock shoes. They are spiky on the rough. They wear them to increase the action of friction on the ground.
Answer:
E. Some charges in the region are positive, and some are negative.
Explanation:
Electric potential is given as;

where;
W is the work done in moving a charge between two points which have a difference in potential
Q is quantity of charge in the given region
If the electric potential at a given point in the region is zero, then sum of the charges in the given region must be equal to zero. For the charges to sum to zero, some will be positive while some will be negative,.
Therefore, the correct statement in the given options is "E"
E. Some charges in the region are positive, and some are negative.
Electromagnetic waves can travel in vaccum but mechanical wave does not
Answer:
(E)56.0 m/s
Explanation:
Height =h=-160 m
Because the wallet moving in downward direction
Time=t=7 s
Final speed of wallet=v=0
We have to find the speed of helicopter ascending at the moment when the passenger let go of the wallet.

Where 
Substitute the values



Option (E) is true
So, the force of gravity that the asteroid and the planet have on each other approximately 
<h3>Introduction</h3>
Hi ! Now, I will help to discuss about the gravitational force between two objects. The force of gravity is not affected by the radius of an object, but radius between two object. Moreover, if the object is a planet, the radius of the planet is only to calculate the "gravitational acceleration" on the planet itself,does not determine the gravitational force between the two planets. For the gravitational force between two objects, it can be calculated using the following formula :

With the following condition :
- F = gravitational force (N)
- G = gravity constant ≈
N.m²/kg²
= mass of the first object (kg)
= mass of the second object (kg)- r = distance between two objects (m)
<h3>Problem Solving</h3>
We know that :
- G = gravity constant ≈
N.m²/kg²
= mass of the planet X =
kg.
= mass of the planet Y =
kg.- r = distance between two objects =
m.
What was asked :
- F = gravitational force = ... N
Step by step :





<h3>Conclusion</h3>
So, the force of gravity that the asteroid and the planet have on each other approximately

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