In tae-kwon-do, a hand is slammed down onto a target at a speed of 10.5 m/s and comes to a stop during the 2.13 ms collision. assume that during the impact the hand is independent of the arm and has a mass of 0.400 kg. what is the magnitude of the impulse?

4.2 kg.m/s

Explanation:

The impulse is the vector greatness that relates force and time, and the momentum is the vector greatness that relates the mass and the velocity of a body. The impulse theorem relates the impulse with the momentum (Q) by the expression:

I = ΔQ

The momentum is Q = mxv, where m is the mass and v the velocity. How the hand stops, the final velocity must be 0, so:

I = mxvf - mxvi

I = 0.4x0 - 0.4x10.5

I = - 4.2 kg.m/s

The minus signal indicates the direction, so the magnitude is 4.2 kg.m/s

explanation:

specific heat is the amount of heat required to raise the temperature of a unit mass of a substance.

answer: the exterior temperature of commercial jet planes as they leave the stratosphere and return to the ground increases steadily.

explanation:

the lower most layer of atmosphere is troposphere which extends from 0 to 12 km above the surface of the earth. the temperature initially decreases as distance is increased from the earth's surface. commercial jets fly in lower part of the stratosphere. the stratosphere extends upto 50 km. the temperature in stratosphere starts rising again due to presence of ozone which traps the uv rays.

thus, when the planes leave the stratosphere and return to the ground, the exterior temperature increases steadily.