To develop muscle tone, a woman lifts a 2.4 kg weight held in her hand. she uses her biceps muscle to flex the lower arm through an angle of 21°. what is the instantaneous angular acceleration if she starts her workout with her arm vertical in the downwards direction? assume the weight is 29 cm from the elbow joint, her forearm has a moment of inertia of 0.245 kg⋅m2, and the muscle force is 850 n at an effective perpendicular lever arm of 1.7 cm in rad/s2.

The energy released by a chemical reaction can be measured using a calorimeter. when barium hydroxide octahydrate crystals are reacted with dry ammonium chloride inside of a coffee cup calorimeter, the temperature of the 18.00 g of water in the calorimeter decreases from 30.0°c to 8.0°c. the equation for calculating energy absorbed or released by a reaction is: where q is the energy released or absorbed, m is the mass of water in the calorimeter, cp is the specific heat of water, and δt is the observed temperature change. if the specific heat of liquid water is 4.19 j/g·°c, how much energy was absorbed by the reaction?

Explain earth's motion, using the terms "precession" and "rotation" in your answer.

A5 foot by 5 foot box culvert is buried 6 feet beneath the surface of the ground. a crosssection of this very long culvert (into and out of the page) is illustrated below. assume that the soil in which the culvert is buried has the following properties: jt = 120 pcf, w = 12%, ko = 0.50, ka = 0.33, and kp = 3.00. calculate the total horizontal force per unit length of culvert (fh) felt on one of the vertical faces of the culvert.