Most of the motion generated by joints in the human body are examples of levers. an example of a third class lever is the forearm; the force which generates the motion is located in‑between the pivot point and the resistance force. the elbow acts as the pivot point, the biceps muscle pulls up on the forearm to move the mass which is held in the hand. imagine someone is holding an object in her hand with her forearm horizontal and her upper arm vertical so her elbow creates a 90 ∘ angle. if her biceps attach to her forearm 0.0425 m from the elbow and make an angle of 30.0 ∘ with the vertical while a 3.14 kg mass is held in her hand 30.75 cm from the elbow, what force f is exerted by the biceps muscle? ignore the mass of the forearm.

The summit of chimborazo, in ecuador, which is at a distance of about 6,384 km from the earth's center. the bottom of the mariana trench, in the western pacific ocean, which is nearly 6,370 km from the center of the earth. on the surface of earth on the equator line.

We want to calculate the total metabolic heat generated by a singing canary taking into account heat transfer by radiation, convection and exhaling air. the air temperature is 20 oc, canary’s body internal and surface temperature is 33oc, external body surface convective heat transfer coefficient is 25.2 w/m2 .k, temperature difference between the inhaled and exhaled air is 4.3 oc, the ventilation rate is 0.74 cc of air per second, specific heat of air is 1.0066 kj/kg.k and density of air is 1.16 kg/m3 . assume the canary’s body to be a cylinder with 7 cm diameter and 9 cm length, and heat exchange is from the side as well as the top and bottom of cylinder. calculate 1) the net rate of heat lost by radiation, assuming heat gained by the bird through radiation from the surroundings is 11.5 w; 2) rate of heat transferred by convection to the surrounding air; 3) rate of heat transferred in the exhaling air without considering any internal evaporation; 4) total metabolic power.

How many times did thomas edison mess up the light bulb