Answer:
Explanation:
The index of refraction is equal to the speed of light c in vacuum divided by its speed v in a substance, or 
. For our case we want to use 
, which for our values is equal to:
Which we will express with 3 significant figures (since a product or quotient must contain the same number of significant figures as the measurement with the <em>least</em> number of significant figures):
Answer:
150 inches (12.5 ft)
Explanation:
The work done to lift the 500 pound block 3 inches should be the same as that to lift the 10 pond object a given distance.
The following is the equation one needs to solve:
therefore solving for the distance "x" gives as the answer (in inches):
which can also be given in feet as: 12.5 ft
Answer:
The time it takes the ball to stop is 0.021 s.
Explanation:
Given;
mass of the softball, m = 720 g = 0.72 kg
velocity of the ball, v = 15.0 m/s
applied force, F = 520 N
Apply Newton's second law of motion, to determine the time it takes the ball to stop;
Therefore, the time it takes the ball to stop is 0.021 s.
gravitational potential is directly proportional to the height of the object relative to a reference line and is given as
PE = mgh
where m = mass of object , g = acceleration due to
gravity and h = height of the object above the reference line .
as the skydiver falls , its height above the ground decrease and hence the gravitational potential energy of the skydiver decrease.
as per conservation of energy , total energy of the skydiver must remain constant all the time . hence the decrease in potential energy appears as increase in kinetic energy by same amount to keep the total energy constant
KE + PE = Total energy
so as the skydiver falls , it gains speed and hence the kinetic energy of skydiver increase since kinetic energy is directly proportional to the square of the speed.
when the parachute opens, the skydiver experience force in upward which tries to balance the weight of the skydiver. hence the speed of the skydiver decrease until upward force becomes equal to the downward force. hence the kinetic energy decrease just after the parachute opens
