You are climbing in the high sierra when you suddenly find yourself at the edge of a fog-shrouded cliff. to find the height of this cliff, you drop a rock from the top; 8.60 s later you hear the sound of the rock hitting the ground at the foot of the cliff. part aignoring air resistance, how high is the cliff if the speed of sound is 330 m/s? suppose you had ignored the time it takes the sound to reach you. in that case, would you have overestimated or underestimated the height of the cliff? a. underestimatedb. overestimated

Boxing gloves are padded to lessen the force of a blow. (a) calculate the force exerted by a boxing glove on an opponent’s face, if the glove and face compress 7.50 cm during a blow in which the 7.00-kg arm and glove are brought to rest from an initial speed of 10.0 m/s. (b) calculate the force exerted by an identical blow in the gory old days when no gloves were used and the knuckles and face would compress only 2.00 cm. (c) discuss the magnitude of the force with glove on. does it seem high enough to cause damage even though it is lower than the force with no glove?

How many times did thomas edison mess up the light bulb

Consider a 1000 w iron whose base plate is made of 0.5 cm thick aluminum alloy 2024-t6 (ρ = 2770 kg/m3 and cp = 875 j/kg°c). the base plate has a surface area of 0.03 m2. initially, the iron is in thermal equilibrium with the ambient air at 22°c. assuming 90% of the heat generated in the resistance wires is transferred to the plate, determine the minimum time needed for the plate temperature to reach 200°c.