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(Show your work in detail.) 1. A cord is used to low er vertically a block of ma

ID: 1782025 • Letter: #

Question

(Show your work in detail.) 1. A cord is used to low er vertically a block of mas M a distance d at a constant dow nward acceleration . Calculate the work done by the cord on the block. 2. There is a 12 story building. Each story is 3 m high. A motor pump of power 1 KW is fitted at the ground. The cross-sectional area of the pipe is Sem2. Upto which story will the water reach? 3. Every minute, 4 10 g mass of sun is being converted to energy per minute. What is the power of the sun in (a) Kilowatts (KW) (b) Horsepower (hp) . Determine the work a hiker must do on a 15.0 kg backpack to carry it up a hill of height h 10 m, as shown in Figure. Determine also the work done by the gravity on the backpack and the net work done on the backpack.

Explanation / Answer

1. Fnet = m a

M g - T = m a = M g / 4

T = 3 M g / 4


Work done = T.d = T d cos(theta)

= (3 M g / 4) (d) cos180

= - 3 M g d / 4