In the figure, a ball is thrown leftward from the left edge of the roof, at height h above the ground. the ball hits the ground 2.40 s later, at distance d = 27.0 m from the building and at angle θ = 59.0° with the horizontal. (a) find h. (hint: one way is to reverse the motion, as if on videotape.) what are the (b) magnitude and (c) angle relative to the horizontal of the velocity at which the ball is thrown (positive angle for above horizontal, negative for below)?

Janelle made a hypothesis bout the uneven temperatures inside her house during winter. she believes that 50% of the ducts are blocked and she plans to investigate. if she wants to prove her hypothesis using scientific processes what should she do next?

Clothing made of several thin layers of fabric with trapped air in between, often called ski clothing, is commonly used in cold climates because it is light, fashionable, and a very effective thermal insulator. so it is no surprise that such clothing has largely replaced thickand heavy old-fashioned coats. (a) consider a jacket made of five layers of 0.1-mm-thick synthetic fabric (k = 0.13 w/m·°c) with 1.5-mm-thick air space (k = 0.026 w/m·°c) between the layers. assuming the inner surface temperature of the jacket to be 28°c and the surface area to be 1.25 m2, determine the rate of heat loss through the jacket when the temperature of the outdoors is 0°c and the heat transfer coefficient at the outer surface is 25 w/m2·°c. (b) what would your response be if the jacket is made of a single layer of 0.5-mm-thick synthetic fabric? what should be the thickness of a wool fabric (k = 0.035 w/m·°c) if the person is to achieve the same level of thermal comfort wearing a thick wool coat instead of a five-layer ski jacket?

Asynthetic fiber used in manufacturing carpet has tensile strength that is normally distributed with mean 75.5 psi and standard deviation 3.5 psi. how is the standard deviation of the sample mean changed when the sample size is increased from n equals 8 to n equals 47