Answer:
m = 3.57
Explanation:
Given that,
Sergei uses a lever to lift a heavy rock. He obtains a 2.5m lever and places the fulcrum 0.7m from the rock.
We need to find the ideal mechanical advantage of Sergei's lever.
It is equal to the ratio of resistance arm to the effort arm. In terms of length it is given by :

So, the ideal mechanical advantage of the lever is 3.57.
Answer:
0.62 rad/s
Explanation:
Angular momentum is conserved.
I₁ ω₁ = I₂ ω₂
where I is moment of inertia and ω is angular velocity.
The total moment of inertia is the sum of the platform's inertia and the boy's.
(I + m r₁²) ω₁ = (I + m r₂²) ω₂
Given I = 1000 kg m², m = 50 kg, r₁ = 4.0 m, r₂ = 3.0 m, and ω₁ = 0.5 rad/s:
(1000 + 50 (4.0)²) (0.5) = (1000 + 50 (3.0)²) ω₂
900 = 1450 ω₂
ω₂ = 0.62 rad/s
Answer:
U=
J
u= 0.708 
Explanation:
diameter= 2 cm

distance= 0.5 mm

Area A= 
Volume v= 

Constant vacuum permittivity

a).
F

b).

