The correct answer to the question is : D) Be moving at a constant velocity.
EXPLANATION:
As per Newton's first laws of motion, every body continues to be  at state of rest or of uniform motion in a straight line unless and until it is compelled by some external unbalanced forces acting on it.
Hence, it is the unbalanced force which changes the state of rest or motion of a body. Balanced force is responsible for keeping the body to be either in static equilibrium or in dynamic equilibrium.
As per the options given in the question, the last one is true for an object under balanced forces.
 
        
             
        
        
        
Answer:
0.5A
Explanation:
Using  ,
,
R is the resistance (in Ohms)
V is the voltage (in V)
I is the current (in A)

I = 0.5A
 
        
             
        
        
        
Answer:
Explanation:
Work done in carrying bricks 
mgh
= 207 x 9.8 x 3.65
-= 7404.4 J 
Work done in compressing gas
PΔV 
Pressure x change in volume 
1.8 x 10⁶ ΔV = 7404.4 
ΔV  = 7404.4  / 1.8 x 10⁶m³
= 4113.33 x 10⁻⁶ m³
= 4113.33 cc 
 
        
                    
             
        
        
        
Answer:
The sound travelled 516 meters before bouncing off a cliff.
Explanation:
The sound is an example of mechanical wave, which means that it needs a medium to propagate itself at constant speed. The time needed to hear the echo is equal to twice the height of the canyon divided by the velocity of sound. In addition, the speed of sound through the air at a temperature of 20 ºC is approximately 344 meters per second. Then, the height of the canyon can be derived from the following kinematic formula:
 (1)
 (1) 
Where:
 - Height, measured in meters.
 - Height, measured in meters.
 - Velocity of sound, measured in meters per second.
 - Velocity of sound, measured in meters per second.
 - Time, measured in seconds.
 - Time, measured in seconds.
If we know that   and
 and  , then the height of the canyon is:
, then the height of the canyon is:



The sound travelled 516 meters before bouncing off a cliff.