Answer:
The time after which the two stones meet is tₓ = 4 s
Explanation:
Given data,
The height of the building, h = 200 m
The velocity of the stone thrown from foot of the building, U = 50 m/s
Using the II equation of motion
                              S = ut + ½ gt²
Let tₓ be the time where the two stones  meet and x be the distance covered from the top of the building
The equation for the stone dropped from top of the building becomes
                             x = 0 + ½ gtₓ²
The equation for the stone thrown from the base becomes
                 S - x = U tₓ - ½ gtₓ²  (∵ the motion of the stone is in opposite direction)
Adding these two equations,
                       x + (S - x) = U tₓ
                                S = U tₓ
                                200 = 50 tₓ
∴                                  tₓ = 4 s
Hence, the time after which the two stones meet is tₓ = 4 s    
 
        
             
        
        
        
Answer:
The answer is "The object's speed relative to S can be greater than or less than its speed relative to S', depending on the actual values."
Explanation:
The S' frame and the object are moving in a positive direction. The object is moving with respect to the S frame so the S frame the rest frame
take the velocity of the object with respect to the rest frame as v and the velocity of the S' frame with respect S frame as v2
relative velocity of the object to the S' frame would be
Vrel = v2- v
This means the Vrel of the object with respect to the S' frame is less than the Vrel  of the object with respect to the S frame
However is the S' velocity is greater than that of the object then the Vrel of the object with respect to the S' frame is greater than the Vrel of the object with respect to the S frame.
This would mean the second option is the answer, the relative speed of the object depends on the actual values.
 
        
             
        
        
        
Answer:
oone side at a time would be hot and the other oone
Explanation:
One side will be hot and the other cold no in-between
 
        
             
        
        
        
I think metal, steel and copper.
        
             
        
        
        
Answer:
Electric field, 
Explanation:
It is given that,
Mass of sphere, m = 2.1 g = 0.0021 kg
Charge, 
We need to find the magnitude of electric field that balances the weight of a plastic spheres. So,

a = g



or

Hence, the magnitude of electric field that balances its weight is  . Hence, this is the required solution.
. Hence, this is the required solution.