When the magnet is placed on the glass, it is attracted to the iron filings. The pattern of the iron filings shows that the lines of force that make up the magnetic field of the magnet. Also, The lines of force of north and south poles attract each other whereas those of two north poles fend off each other.
-- Before Adrian left the airplane, his gravitational potential energy was
(mass) x (gravity) x (height) = (80kg) x (9.81m/s²) x (1,000m) = 784,800 joules
-- When he reached the ground, his kinetic energy was
(1/2) x (mass) x (speed)² = (40kg) x (5m/s)² = 1,000 joules
-- Between the airplane and the ground, the Adrian lost
(784,800 joules) - (1,000 joules) = 783,800 joules
Where did all that energy go ?
Energy never just disappears. If it's missing, it had to go somewhere.
The Adrian used 783,800 joules of energy to push air our of his way
so that he could continue his parachute jump, and reach the ground
in time to be home for dinner.
1.5 / 0.5 = 3 I believe this is the right answer
The velocity of the wave on the string is given by
Solving the above equation,
The frequency of the wave 
and wave length is 
The velocity is 
Substituting numerical values,
The length of the string is 
