1. A boy is sitting on a swing at a maximum height of 5m above the ground. When
ID: 1783455 • Letter: 1
Question
1. A boy is sitting on a swing at a maximum height of 5m above the ground. When the swing passes through the mean position which is 2m above the ground, what will be his velocity at mean position? Water flows over a waterfall at the rate of 35000 kg per 50 min. How much power is generated by the falling water? A 2kg block is dropped from a height of 0.4m on a spring of force constant 1960N/m. What will 2. 3. be the maximum compression of the spring? If the original height of the rock is 3m. Calculate rock's speed when it has fallen to 1m above the ground. A 1000kg roller coaster moves from position 1to 2 then to position 3. 4. 5. 10m 15mExplanation / Answer
1) H= maximum height = 5m
h= 2m
At maximum height , kinetic energy .K.E1 = 0
potential energy , P.E1 = mgH
at mean position , K.E2 = (1/2)*m*V2
potential energy ,P.E2 = mgh
from conservation of energy, total energy will remain same.So
K.E1 + P.E1 = K.E2 + P.E2
0 + mgH = (1/2)*m*V2 + mgh
mgH= m[(1/2)*V2 + gh]
gH - gh = (1/2)*V2
V(velocity at mean position) = ( 2[ 9.8(5-2)]1/2
V= 7.67 m/s
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