Answer:
8, 8 W
Explanation:
The useful power of 1 Light Emitting Diode is

Total power required is 1.6 W
Number of Light Emitting Diodes would be

The number of Light Emitting Diodes is 8.
Power would be

The power that is required to run the Light Emitting Diodes is 8 W
Here in this case since there is no torque about the hinge axis for the system of bullet and block then we can say that angular momentum of this system will remain conserved


here we will have
L = 0.250 m
v = 385 m/s
m = 1.90 gram
now moment of inertia of the plate will be



now from above equation


The force applied by the man is 60 N
Explanation:
We can solve this problem by applying Newton's second law, which states that:
(1)
where
is the net force acting on the child+cart
m is the mass of the child+cart system
a is their acceleration
In this problem, we have:
m = 30.0 kg is the mass

And there are two forces acting on the child+cart system:
- The forward force of pushing, F
- The force resisting the cart motion, R = 15.0 N
Therefore we can write the net force as

where R is negative since its direction is opposite to the motion
So eq.(1) can be rewritten as

And solving for F,

Learn more about Newton's second law:
brainly.com/question/3820012
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We need the power law for the change in potential energy (due to the Coulomb force) in bringing a charge q from infinity to distance r from charge Q. We are only interested in the ratio U₁/U₂, so I'm not going to bother with constants (like the permittivity of space).
<span>The potential energy of charge q is proportional to </span>
<span>∫[s=r to ∞] qQs⁻²ds = -qQs⁻¹|[s=r to ∞] = qQr⁻¹, </span>
<span>so if r₂ = 3r₁ and q₂ = q₁/4, then </span>
<span>U₁/U₂ = q₁Qr₂/(r₁q₂Q) = (q₁/q₂)(r₂/r₁) </span>
<span>= 4•3 = 12.</span>