kinetic energy integral

**winterwyrm** · October 4th 2008, 10:55 AM

A 2.1 kg block is initially at rest on a horizontal frictionless surface when a horizontal force in the positive direction of an x axis is applied to the block. The force is given by

(x) = (4.2 - x2)

N, where x is in meters and the initial position of the block is x = 0. (a) What is the kinetic energy of the block as it passes through x = 3.3 m? (b) What is the maximum kinetic energy of the block between x = 0 and x = 3.3 m?
Thanks a ton.

**skeeter** · October 4th 2008, 11:35 AM

I'm assuming that the force you posted is $(4.2 - x^2)\vec{i}$

(a) ... $\Delta KE = W = \int_0^{3.3} (4.2 - x^2)\, dx$

(b) ... $\frac{dW}{dx} = \frac{d}{dx} \int_0^x (4.2 - t^2) \, dt$

once you find it, set $\frac{dW}{dx} = 0$ and determine the x-value that minimizes W.

**winterwyrm** · October 4th 2008, 12:15 PM

you must be a physics type, great job. But shouldn't it be the maximum W?

**skeeter** · October 4th 2008, 02:08 PM

yea ... was thinking max-min and the min stuck in my head.

Thread: kinetic energy integral

LinkBack

Thread Tools

Display

kinetic energy integral

Similar Math Help Forum Discussions

kinetic energy during energy levels

kinetic energy PDE

kinetic energy

kinetic energy

kinetic energy

Search Tags