Answer:
Explanation:
Given
mass of person is m
Distance between bridge and river is h
chord has an un-stretched length of 
Let spring constant be k
Person will just stop before hitting the river
Conserve energy i.e. Potential Energy of Person is converted in to elastic energy of chord
Thus
Answer: B - 8
Explanation: 8 protons because number of protons is equal to number of atoms in the nucleus.
Answer:
Explanation:
During the first .8 s , the elevator is under acceleration . It starts from initial velocity u = 0 , final velocity v = 1.2 m /s , time = .8 s
v = u + at
1.2 = 0 + .8 a
a = 1.2 / .8
= 1.5 m /s²
During the acceleration in upward direction , let reaction force of ground on man be R .
Net force on man = R - mg
Applying Newton's 2 nd law
R - mg = ma
R = m ( g + a )
= 72 ( 9.8 + 1.5 )
= 813.6 N .
This reaction force will be measured by spring scale , so reading of spring scale will be 813.6 N .
This is called average speed.Its really simple
