Answer:
Explanation:
mass of 1 L water = 1 kg . 
200⁰F = (200 - 32) x 5 / 9 = 93.33⁰C .
260.928 K = 260.928 - 273 = - 12.072⁰C . 
water is at higher temperature . 
Let the equilibrium temperature be t . 
Heat lost by water = mass x specific heat x  fall of temperature 
= 1 x 4.2 x 10³ x ( 93.33 - t ) 
Heat gained by copper 
= .25 x .385 x 10³ x ( t +  12.072 ) 
Heat lost = heat gained 
 1 x 4.2 x 10³ x ( 93.33 - t ) = .25 x .385 x 10³ x ( t +  12.072 ) 
 93.33 - t = .0229 ( t + 12.072)
93.33 - t = .0229 t + .276 
93.054 = 1.0229 t 
t = 90.97⁰C . 
 
        
             
        
        
        
The normal force acting on the object is 500 N in the upward direction
<u>Explanation:</u>
As George is applying a downward force, the normal force will be in the upward direction. The normal force will be exerted due to the acceleration due to gravity exerted on the object. 
So, as per Newton's second law, the normal force acting on the object can be measured by the product of mass of the object and the acceleration due to gravity acting on the object. 
But as the acceleration due to gravity is a downward acting acceleration and the normal force is a upward acting force, so the acceleration will be having a negative sign in the formula.

Here, acceleration due to gravity g = -10 m/s² and mass is given as 50 kg, then
 Normal force = 50 × (-10) = -500 N
So, the normal force acting on the object is 500 N in the upward direction.
 
        
             
        
        
        
Answer: 8000N
Explanation: since it is frictionless that means it has 100% efficiency therefore the mechanical advantage is 1 meaning the load equals to the effort 
 
        
             
        
        
        
Answer:
The answer is C because they have to be close to be able to interact
 
        
             
        
        
        
The electric field is always perpendicular to the surface outside of a conductor. TRUE
<span> If an electron were placed on an electric field line, it would move in a direction perpendicular to the field. FALSE, it would move in an anti-parallel direction because its charge is negative </span>
 
<span>Electric field lines originate on positive charge and terminate on negative charge. TRUE ; but they can also go to infinity </span>
 
It is possible for two electric field lines to cross each other.
<span> Usually FALSE; though technically possible at special points where field is zero. </span>
 
If an electron and a positron were in the presence of a very strong electric field, they would move away from each other.
<span> TRUE; one is positive, and one is negative. If the field is strong enough, the action of the field will overcome the mutual attraction between them </span>
 
It is not possible for the electric field to ever be zero. FALSE: it IS possible, inside a conductor for instance
   
If a proton were placed on an electric field line, it would move in a direction anti-parallel to the field.
<span> FALSE: being positive, it would move in the SAME direction as the field</span>ic