who can answer this physic question?

Question

A baseball player throw a ball with 20 m\s former velocity .and the other player at that surface catch the ball when the velocity of the ball decrease to 16 m/s . How much work have done for prevailing from the resistance of the air? The mass of the ball is 250 gr.

Answer 1

work = change of kinetic enegy
W = 1/2 m (vf² - vi²)
W = 0.5 * (0.250 kg) * (16² - 20²) m²/s²
W = -18 J

Answer 2

Work done = loss in Kinetic Energy = 1/2 (.25) (20^2-16^2)

= .125 (400-256)

= .125 x 144 J = 18 J

Answer 3

Hey, just thougt I would tell you how stupid you are, so that I get a point.

If you wanna pass your physics exam, you are going to have to learn some of this stuff. Learning formula parror fasion will not work, as you won't know how to apply them.

However, that being said......if stupid little bitches like you keep ******* it all up in the pursuit on an easy life....it means less people graduate physics, leaving a shortage of physics graduates.....meaning more money for me!!!! While you work in a shop selling handbags.

Good luck with that, I can see that working for you.

hugs

A N Other girl PASSING physics!

Answer 4

Ok, here's how you do it...

Work = initial kinetic energy - final kinetic energy

why? i'll explain it to you

first you need to get the acceleration, since you don't have the time it takes to get to the second speed you use the formula.

Remember that work=force*distance

since you don't have the dinstance you have to get it with equations an the first thing you need to know is the acceleration.

Force = mass*acceleration

you get what acceleration is:

acceleration = force/mass

now that you have the acceleration you use this formula to get the distance.

distance= (final velocity + initial velocity)*time/2

(final velocity + initial velocity)/2 is the average velocity.

since we don't know the time, we use this other equation in order to get it.

acceleration=(final velocity-initial velocity)/time

so time would be

time = (final velocity - initial velocity)/acceleration

now you combine the two equations.

distance= (final velocity + initial velocity)*(final velocity - initial velocity)/(acceleration*2)

remember that

acceleration = force/mass

so

distance= (final velocity + initial velocity)*(final velocity - initial velocity)/(force*2/mass)

or

distance = mass*(final velocity + initial velocity)*(final velocity - initial velocity)/(force*2)

now you can get the work

work = force*distance

work = force * mass*(final velocity + initial velocity)*(final velocity - initial velocity)/(force*2)

or

work = mass*(final velocity + initial velocity)*(final velocity - initial velocity)/2

or

work = mass*(final velocity squared - initial velocity squared)/2

remember that

change in kinetic energy = 1/2*mass*initial velocity squared-1/2*mass*final velocity squared

wich is

change in kinetic energy = 1/2*mass(final velocity squared-initial velocity squared)

so combining the last two equation you get

work = change of kinetic energy.

so in your problem the work would be

work = (0.25kg)*1/2*((20m/s)*(20m/s)-(16m/s)*(16m/s))
work = 18 J

Answer 5

Do you EVER???? answer your own homework?

Answers aren't worth a lot unless backed up by a combination of intelligence and knowledge. Enjoy your ingnorance and practice the following:

"Would you like extra fris with that, Sir?".

or the variant:
"Would you like onion rings, Madam?"

Answer 6

the answer is 18 Nm