A man weighing 180 lbf pushes a block weighing 100 lbf along a horizontal plane. the dynamic coefficient of friction between the block and plane is 0.2. assuming that the block moves at a constant speed, how much work is required to move the block 100 ft considering the (a) the block and (b) the man as the system.

Question

Physics

Madilyn Kaufman

5 December, 13:01

A man weighing 180 lbf pushes a block weighing 100 lbf along a horizontal plane. the dynamic coefficient of friction between the block and plane is 0.2. assuming that the block moves at a constant speed, how much work is required to move the block 100 ft considering the (a) the block and (b) the man as the system.

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Answers (1)

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Lucian Scott · Answer 1

The first thing you should know is that the work is defined as:

W = F * d

Where

F = force

d = displacement

We have then

(a) the block

F = (0.2) * (100) = 20

d = 100

W = (20) * (100) = 2000 ft. lbf

(b) the man as the system.

F = (0.2) * (100 + 180) = 56

d = 100

W = (56) * (100) = 5600 ft. lbf

answer:

(a) 2000 ft. lbf

(b) 5600 ft. lbf