Work is done when spring is extended or compressed. Elastic potential energy is stored in the spring. Provided inelastic deformation has not happened, the work done is equal to the elastic potential energy stored.
 
        
                    
             
        
        
        
Answer:
The hiker followed a road heading north for 2 miles in 30 minutes.
Explanation:
In order to describe the motion of an object, distance covered and time taken must be required. The total path covered by an object is called the distance travelled. 
The hiker followed a road heading north for 2 miles in 30 minutes. This describes the motion of hiker. The motion shows how fast the hiker is moving.  
Distance, d = 2 miles = 3218.6 m
times, t = 30 minutes = 1800 seconds
So, we can say that the hiker is moving with a speed of 1.78 m/s in north direction.
Hence, this is the required solution.
 
        
                    
             
        
        
        
Answer:
Explanation:
KE = ½Iω²
ΚΕ = ½(mL²/3)ω²
ΚΕ = ½(0.63(0.82²)/3)4.2²
ΚΕ = 1.24541928
KE = 1.2 J
 
        
             
        
        
        
Answer: 
Explanation:
Given
Diameter of the rod 
length of rod is 
Resistivity of silicon is 
cross-section of the rod 

Resistance of rod is  R


Current is given by 

 
        
             
        
        
        
The equation that relates distance, velocities, acceleration, and time is,
                   d = V₀t + 0.5gt²
where d is distance,
V₀ is the initial velocity,
t is time, and 
g is the acceleration due to gravity (equal to 9.8 m/s²)
(1) Dropped rock,
                  (3 x 10² m ) = 0(t) + 0.5(9.8 m/s²)(t²)
The value of t from this equation is 24.73 s
(2) Thrown rock with V₀ = 26 m/s
                (3 x 10² m) = (26)(t) + 0.5(9.8 m/s²)(t²)
The value of t from the equation is 5.61 s
The difference between the tim,
        difference = 24.73 s - 5.61 s
          difference = 19.12 s
<em>ANSWER: 19.12 s</em>