Answer:
(A) 60 J
Explanation:
At state 1
KE₁=100 J
At state 2
KE₂ = 0
U₂=80 J
Given that surface is rough so friction force will act in opposite to the direction of motion
Lets take work done by friction = Wfr
From work power energy
Work done by all forces = Change in kinetic energy
Wfr + U₂=ΔKE
Wfr+80 = 100
Wfr= 20 J
Now when book slides from top position then
Wfr+ U = KEf - KEi
-20 + 80 = KEf-0
KEf= 60 J
(A) 60 J
Answer:
He is warmed up now
Explanation:
His muscles are better and stretched now
Answer:
B. counterclockwise
Explanation:
We shall apply Lenz's law to find direction of induced current . According to it , direction of induced current is such that the magnetic field produced by it will try to nullify the change in magnetic field that produces it. Increase in magnetic field in down ward direction is producing it so to nullify it , magnetic field induced will be in upward direction. For it current induced will be anticlockwise.
Answer:
(A) 
(B) s = 146.664 m
Explanation:
We have given car starts from the rest so initial velocity u = 0 m /sec
Final velocity v = 88 km/hr
We know that 1 km = 1000 m
And 1 hour = 3600 sec
So 
Time is given t = 12 sec
(A) From first equation of motion v = u+at
So 

So acceleration of the car will be 
(b) From third equation of motion 
So 
s = 146.664 m
Distance traveled by the car in this interval will be 146.664 m