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ID: 1631157 • Letter: S
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story Bookmarks Window Help saplinglearning.com 7/14/2017 10:00 PM 0 76.7/100 () 7/11/2017 02:54 PM Gradebook Print -nd Periodic Tate Calculator Question 19 of 20 Sapling Learning Sir Dudley the Dextrous is loading cannons on top of the castle's tallest towers in preparation for an expected attack. He slips, and a 10.0 kg cannonball rolls to the edge of the tower (which has a perfectly horizontal surface), and fals to the ground below. It takes the cannonball 2.15 seconds to fall to the ground, and air resistence is negligible. How much work is done by gravity on the falling cannonbalir? Number 2524.48 J During the tall, what is the average power transfer to the cannonball due to the force of gravity? Number 1174.17 W Incorrect Previous #Try Again e Next ExtrExplanation / Answer
(a) Since the floor is perfectly horizontal therefore the initial velocity in the vertical direction would be zero.
Now the distance covered by the ball in 2.15 seconds
S= ut + 0.5at2
where S is distance covered , a is acceleration , u is initial velocity in vertical direction ,
S = 0*2.15 + 0.5*9.81*2.152
S = 22.673 m
Force = mass*g = 10*9.81 = 98.1 N
Work done by the gravity force = force*distance = 98.1*22.673 = 2224.257 J
(b) Power = energy /time
Power = 2224.257 /2.15 =1034.54 W
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