The deck of a bridge is suspended 235 feet above a river. If a pebble falls off the side of the bridge, the height, in feet, of the pebble above the water surface after t seconds is given by y = 235 − 16t^2. Required:
a. Find the average velocity (in ft/s) of the pebble for the time period beginning when t = 2 and lasting the following amount of time.

1. 0.1 sec:
2. 0.05 sec:
3. 0.01 sec:

b. Estimate the instantaneous velocity (in ft/s) of the pebble after 3 seconds. ft/s.

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.

Atotal charge of –6.50 µc is uniformly distributed within a sphere that has a radius of 0.150 m. what is the magnitude and direction of the electric field at 0.300 m from the surface of the sphere? a) 2.89 × 105 n/c, radially inward b) 6.49 × 105 n/c, radially outward c) 4.69 × 105 n/c, radially inward d) 9.38 × 105 n/c, radially outward e) 1.30 × 106 n/c, radially inward

Write down two additional questions about earth's magnetic field that will make your presentation more informative.