Firemen are shooting a stream of water at a burning buildingusing a high-pressure hose that shoots out the water with a speedof 25.0 m/s. as it leaves the end of the hose. Once it leaves thehose, the water moves in projectile motion. The firemen adjust theangle of elevation α of the hose until the water takes3.00 s to reach the building 45.0 m away. You can ignore airresistance; assume that the end of the hose is at grounglevel.
a) Find the angle of elevation αb) Find the speed and acceleration of the water at the highestpoint in its trajectoryc) How high above the ground does the water strike thebuilding, and how fast is it moving just before it hits thebuilding?
Answers: 2
Physics, 21.06.2019 14:40
Astring that is fixed at both ends has a length of 1.05 m. when the string vibrates at a frequency of 91.0 hz, a standing wave with five loops is formed. (a) what is the wavelength of the waves that travel on the string? (b) what is the speed of the waves? (c) what is the fundamental frequency of the string?
Answers: 2
Physics, 22.06.2019 02:00
Which statements about tornadoes are true? check all that apply. (a) about 12,000 tornadoes hit the united states every year. (b) a tornado looks like a funnel. (c) tornadoes are deadly atmospheric storms that cause millions in damages each year. (d) tornadoes can reach wind speeds of more than 300 miles per hour. (e) kansas is the state with the most tornadoes. (f) you will always notice a funnel before a tornado strikes.
Answers: 2
Physics, 22.06.2019 18:00
Cells in the nervous system have a potential difference of 70 mv across the cell membrane separating the interior of the cell from the extracellular fluid. this potential difference is maintained by ion pumps that move charged ions across the membrane. is this an emf? select the correct answer and explanation. 1)no. the ion pumps cannot separate charges; thus, they cannot create a potential difference. 2)yes. the ion pumps cannot separate charges, but they still can create a potential difference. 3)yes. the ion pumps can actively separate charge; thus, they can create a potential difference. 4)no. the ion pumps can separate charges, but they cannot create a potential difference.
Answers: 1
Physics, 22.06.2019 19:30
A47.2 g block of copper whose temperature is 480 k is placed in an insulating box with a 91.8 g block of lead whose temperature is 200 k. (a) what is the equilibrium temperature of the two-block system? (b) what is the change in the internal energy of the two-block system between the initial state and the equilibrium state? (c) what is the change in the entropy of the two-block system? the heat capacities of copper and lead are 386 j/kg·k and 128 j/kg·k, respectively.
Answers: 1
Firemen are shooting a stream of water at a burning buildingusing a high-pressure hose that shoots o...
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