Answer:
Explanation:
the unit of work is derived unit because joule is defined the work done by the force aftab 1 newton causing the displacement of one metre something newton metre(n-m) is also used to measuring work
Answer:
Minimum coefficient of kinetic friction between the surface and the block is 
.
Explanation:
Given:
Mass of the block = M
Spring constant = k
Distance pulled = x
According to the question:
<em>We have to find the minimum co-efficient of kinetic friction between the surface and the block that will prevent the block from returning to its equilibrium with non-zero speed. </em>
So,
From the FBD we can say that:
⇒ Normal force, 
<em>...equation(i)</em>
⇒ Elastic potential energy, 
= 
<em> ...equation (ii)</em>
⇒ Frictional force, 
= 
<em> ...equation (iii)</em>
⇒ Plugging (i) in (iii).
⇒ 
Now,
⇒ As we know that the energy lost due to friction is equivalent to PE .
⇒ 
<em>...considering PE as</em> 
or 
.
Arranging the equation.
⇒ 
⇒ 
<em>...eliminating x from both sides.</em>
⇒ 
<em>...dividing both sides wit Mg.</em>
Minimum coefficient of kinetic friction between the surface and the block is .
Answer:
The speed of molecule decreases and temperature also decreases
Explanation:
Kinetic energy of the molecules of a subsance is directly proportional to the temperature of molecule So as the kinetic energy decrease, temperature also decreases. decreses their speed.
Answer:
2.72 m
Explanation:
wavelength of sound λ = velocity / frequency
= 340 / 1200
= .2833 m
Distance of point of first constructive interference
= λ D / d ( D is distance of the screen and d is distance between source of sound.
Here D = 12.5 m
d = 1.3 m
λ D / d= ( .2833 x 12.5) / 1.3
= 2.72 m
Distance of point of first constructive interference = 2.72 m
