What is it's kinetic Engergy?

Question

a 7.00 kg bowling ball falls froma 2.00 m shelf. Just before hitting the floor, what will be its kinetic energy? (g=9.80 m/s^2)

I know KE= (1/2)mv^2, obviously m=7.00 kg, but what do you do with the 2 m and gravity.

I want numbers and equations people, not words.

How do I find the acceleration?

I mean the velocity.....oops

Answer 1

Kinetic is related to movement or action. You must consider that a still ball on a shelf first counts with Potencial Energy (PE) due to gravity. PE converts to KE as the ball falls to the ground. On the shelf the ball is 100% PE (still) and when it hits the floor is 100% KE (maximum speed).

Since all the KE of the ball comes from its former PE, you can say:

PE= mgh (by definition); and KE=PE=mgh (in Joules units, or J)

Answer 2

Kinetic energy is energy of motion, expressed in units of kilogram-meters/second^2, which you can get from looking at the formula.

Kinetic energy increases with time for an object falling in a gravitational field because its velocity increases until something stops it, and the energy is converted into sound, heat and compression. If the energy did not dissipate, the object would bounce back to its original height, then fall and bounce back forever in an "ideal" collision. Most objects do bounce a little when they fall, but not for long in the real world. To move it back to where it started, work must be done against gravity.

Since distance = 1/2 g t^2 = 2.00 meters, solve for t = sqrt (2.00/4.90) = 0.639 seconds, then the velocity = g t = 9.80 * 0.639 = 0.626 m/s, and KE = (7.00 * 0.626^2) / 2 = 1.37 kg-m/s^2.

Answer 3

The potential energy it has in the form mgh, will be converted entirely to kinetic energy when the ball falls the 2.0 meters. So we can equate the kinetic energy with the potential energy and solve for v:

mgh=1/2 m v^2
v=sqrt(2gh)

Answer 4

First of all, using the height of the shelf and the acceleration due to gravity, find out the time to hit the floor and the velocity at impact. Multiply that by the mass.

Answer 5

The energy possessed by a body because of its motion, equal to one half the mass of the body times the square of its speed.


if a baseball is thrown at a car, it bounces off and deflects another direction using kinetic energy

Answer 6

KE = mgh (m=mass, g=gravity, h=height)

KE = 7 x 9.8 x 2 = 137.2 Joules.

KE = ½mv²

Velocity: v = √ (2KE÷m)

Answer 7

you must use the gravity 9.8m/s^2 and the distance (2m) to figure out its velocity at the moment of impact. Then plug that into the formula.

Answer 8

its th e theory that all energy, and matter combonations, t hat produce, an interesting effect, when combined. will if ever all found, lead to the development, of
the understanding of why now and until the end, enrgy absoorbed


let me start the end over again,
energy absorbed+enrgy used=time spent

Answer 9

kinetic energy is energy in motion