Answer:
he will not be drowned
Explanation:
Question says , the height of the student = 4 feet,
Depth of the pool( in feet ) be x ( say ) which is less than 4 feet,
Clearly, the depth of the pool < height of the student,
This means, if the student goes for swimming in the pool, however he does not know swimming, he will not be drowned until he is suffering from an injury or external force.
Because the sun stays in the same place but your brain makes you think the sun is descending so your eyes think you're higher than the sun
Answer:
The mass of the cargo is 
Explanation:
From the question we are told that
The radius of the spherical balloon is 
The mass of the balloon is
The volume of the spherical balloon is mathematically represented as

substituting values


The total mass the balloon can lift is mathematically represented as

where
is the density of helium with a value of

and
is the density of air with a value of

substituting values


Now the mass of the cargo is mathematically evaluated as


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 .