Answer:
C is the best answer because we all know that clock is part of our daily lives but we don't know the about its background
Explanation:
A worker picks up the bag of gravel. We need to find the speed of the bucket after it has descended 2.30 m from rest. It is case of conservation of energy. So,

h = 2.3 m

So, the speed of the bucket after it has descended 2.30 m from rest is 6.71 m/s.
Explanation:
"Carry energy" and "Follow a patter
this is right one
Answer:
a)- 1.799 rad/sec²
b)- 17.6 x 10ˉ³Nm
Explanation:
ω₀ = 720 rev/min x (1 min/60 sec) x (2π rad / 1 rev) = 24π rad/s
a) Assuming a constant angular acceleration, the formula will be
α = (ωf -ω₀) / t
As final state of the grindstone is at rest, so ωf =0
⇒ α = (0-24π) / 41.9 = - 1.799 rad/sec²
b)Moment of inertia I for a disk about its central axis
I = ½mr²
where m=2kg and radius 'r'= 0.099m
I = ½(2)(0.099²)
I = 9.8 x 10ˉ³ kgm²
Next is to determine the frictional torque exerted on the grindstone, that caused it to stop, applying the rotational equivalent of the Newton's 2nd law:
τ = I α =>(9.8 x 10ˉ³)(- 1.799)
τ = - 17.6 x 10ˉ³Nm
(The negative sign indicates that the frictional torque opposes to the rotation of the grindstone).
The internal energy increases 1.5 times
Explanation:
the internal energy of a mono atomic gas is given by E= 3/2kT
T1= 27⁰C= 27+273=300 K
T2=177⁰C= 177+273=450 K
E1= 3/2 k (300)
E2=3/2 k (450)
so E2/E1=[3/2 k (450)][3/2 k (300)]
E2/E1=450/300
E2= 1.5 E1
so the internal energy increases by a factor of 1.5