Answer:
A! I already went through this unit. Joule.
Explanation:
Answer:
Torque decreases .
Explanation:
The tape is pulled at constant speed , speed v is constant , so there is
v = ω r where ω is angular speed and r is radius , As radius decreases , angular speed ω increases , So there is angular acceleration .
Let it be α . Let I be moment of inertia of reel .
Reel is in the form of disc
I = 1/2 m r²
I x α = torque
1/2 m r² x α = torque
As the reel is untapped , its mass decreases , r also decreases , so torques also decreases .
Answer:
a. 
b. 
Explanation:
The inertia can be find using
a.





now to find the torsion constant can use knowing the period of the balance
b.
T=0.5 s

Solve to K'


Answer:16.096
Explanation:
Given
mass of dog
mass of boat
distance moved by dog relative to ground=
distance moved by boat relative to ground=
Distance moved by dog relative to boat=7.8m
There no net force on the system therefore centre of mass of system remains at its position
0=
0=

i.e. boat will move opposite to the direction of dog
Now

substituting
value



now the dog is 22.5-6.403=16.096m from shore
The action force is when you are putting your weight on the chair when you are sitting down. the reaction force is the force exerted by the chair that pushes up on your body and is equal to your weight.