An 80 kg volleyball player lands from a jump and tries to stop her forward motion. The normal contact force exerted by the floor on her shoes is 2000 N. The friction force exerted by the floor on her shoes is 600 N acting backward on the player. What is the resultant ground reaction force exerted by the floor on the volleyball player's shoes?

The answer to the question is

The resultant ground reaction force exerted by the floor on the volleyball player's shoes = 2088.06 N

Explanation:

To solve the queston we list out the variables thus

Mass of volley ball player = 80 kg

Normal force exerted on her shoes by the floor N =2000 N

friction force, f, exerted on her shoes backwards = 600 N

The resultant ground reactive force, R, is given by

R² = N² + f² = 2000² + 600² =  4000000 + 360000 = 4360000

Therefore R = √(4360000) =  2088.06 N

The direction of the force = atan (2000/600) = 73.3 ° clocwise or 106.699 ° counter clockwise

b.

the accuracy of the data.

it can be observed without changing the identity of the object.

it depends on what substance you're talking about as well as many other factors. in quantum mechanics, the observation of particles affects the observers ability to measure certain properties. for example: you can know the velocity of a particle, but you can't know it's position; or you can know it's position, but not it's velocity. it's like trying to find out where a grain of sand is by throwing other grains of sand at it. once you find out where it is, it's been moved. it's also like trying to find an answer to the question of whether or not a tree falling in a forest makes a sound if nobody is there to hear it. paradoxically, the only way to find out is to be there and hear it.