The answer should be B. According to the conservation of energy, the energy cannot be created nor destroyed, but it can be transformed. Since the object is moving down, that means its height is decreasing, causing the potential energy decreasing and the kinetic energy  increasing to fulfill the conservation law. 
        
             
        
        
        
Answer:
R = 5.73 m
Explanation:
For an angle of rotation through 21 degree we know that
arc length is given as

now we know that
Arc = 2.1 m
Angle = 21 degree

so now we have



 
        
             
        
        
        
Answer:
given,
mass of the skier = 70.1 Kg
angle with horizontal, θ = 8.6°
magnitude of the force,F = ?
a) Applying newton's second law
     
 
  velocity is constant, a = 0 
     
 
    
    
   
b) now, when acceleration, a = 0.135 m/s²
     
 
  velocity is constant, a = 0.135 m/s₂ 
    
    
   
 
        
             
        
        
        
Explanation:
When the wire is connected to a battery, the compass needle moves and changes its position. This happens because the needle magnetizes the copper wire, thus,  creating a force. 
While the current in the wire produces a magnetic field and exerts a force on the needle. The insulation on the wire becomes energized and exerts a force on the needle. Hence, the compass needle moves and changes its position.