Answer:
Explanation:
Tension provides centripetal force in the circular motion . In circular motion work done by force = torque x angle 
torque is zero as , centripetal force passes through axis of rotation that is center. 
So work done by centripetal force  = 0 
So work done by tension on M = 0 
 
        
             
        
        
        
Answer:
When a ray of light falls on a glass slab normally, the angle between normal and incident ray is zero.
 
        
             
        
        
        
Answer:
Initial velocity = 10 m/s
θ = 60°
This is the case of projectile motion
So the horizontal component of velocity 10 m/s  =  10 cosθ
u = 10 cosθ
u = 10 cos 60°
u=5 m/s
 x= 5 m
So in the horizontal direction
x = u .t 
5 = 5 .t
t = 1 sec  The vertical component of velocity 10 m/s = 10 sinθ
Vo= 10 sinθ
Vo= 10 sin 60°
Vo = 8.66 m/s
 
 
 
 
 
 
h=3.75 m
So height of robot = 3.75 - 0.75 m
    height of robot =3 m
 
 
        
             
        
        
        
Answer:
The runner's acceleration was 
Explanation:
<u>Constant Acceleration Motion</u>
It's a type of motion in which the velocity of an object changes by an equal amount in every equal period of time.
Being a the constant acceleration, vo the initial speed, vf the final speed, and t the time, the following relation applies:

Solving for a:

The runner speeds up from vo=5 m/s to vf=9 m/s in t=4 seconds, thus:


The runner's acceleration was 
 
        
             
        
        
        
Length of the cord..........................................................