Answer:
D
Explanation:
D) The overall work done by gravity is zero
This statement is correct .
If m be the mass of each of the children and h be the height of tower
work done by gravity on the boys in going up = - mgh
it is so because force applied by gravity = mg downwards and displacement
is upwards
work done will be negative = - mgh
Work done by gravity on boys when they come down = + mgh because both force and displacement are downwards .
Hence total work done = - mgh + mgh = 0.
The children will have same kinetic energy as the inclined surface is friction-less so no energy will be dissipated hence addition of energy to boys in both the cases will be same.
Answer:
110.87 dB
Explanation:
(I got it right on Acellus)
I= P/4(pi)r^2 = 60/4(pi)6.25^2
60/4(pi)6.25^2=0.12223
B=10log(I/Io)
B=10log(0.12223/1*10^-12) = 110.87 dB
111 in sigfigs
Answer:
The current is 
The direction is anti-clockwise
Explanation:
The diagram for this question is shown on the first uploaded image
From the question we are told that
the length of the conducting rod is 
The resistance is 
The magnetic field is 
The speed of the rod is 
The emf induced is
substituting values we have
From ohm law the induced current would be
substituting values we have
The direction anticlockwise this because according to lenze law the current due to change in magnetic field will act in the opposite direction of the force causing the magnetic field to change
D. Light as light is a wave
Answer: <em>An object at rest remains at rest, or if in motion, remains in motion at a constant velocity unless acted on by a net external force.</em>
Explanation: meaning, an object will continue in its same direction until stopped or acted upon by another force.
