Question

Ten bricks, each 6.0 cm thick and mass 1.5 kg, lie flat on a table. How much work is required to stack them over eachother

Answer 1

The workdone required to stack them over each other is 39.69 J

What is workdone?

This is defined as the product of force and distance moved in the direction of the force.

Workdone (Wd) = Force × distance (d)

But

Force = weight = mass × acceleration due to gravity

w = mg

Distance (d) = height (h)

Thus,

Wd = weight × height

How to determine the workdone in stacking them together

We'll begin by calculating the weight of each bricks

• Mass of each bricks (m) = 1.5 Kg
• Acceleration due to gravity (g) = 9.8 m/s²
• Weight of each bricks (W) =?

W = mg

W = 1.5 × 9.8

W = 14.7 N

Next, we shall determine the work done in stacking the 2nd on the 1st brick and so on..

Workdone in stacking the 2nd on the 1st

• Weight (W) = 14.7 N
• Height (h) = 6 cm = 6 / 100 = 0.06 m
• Workdone (Wd) = ?

Wd = Weight × height

Wd = 14.7 × 0.06

Wd = 0.882 J

Workdone in stacking the 3rd

• Weight (W) = 14.7 N
• Height (h) = 0.12 m
• Workdone (Wd) = ?

Wd = Weight × height

Wd = 14.7 × 0.12

Wd = 1.764 J

Workdone in stacking the 4th

• Weight (W) = 14.7 N
• Height (h) = 0.18 m
• Workdone (Wd) = ?

Wd = Weight × height

Wd = 14.7 × 0.18

Wd = 2.646 J

Workdone in stacking the 5th

• Weight (W) = 14.7 N
• Height (h) = 0.24 m
• Workdone (Wd) = ?

Wd = Weight × height

Wd = 14.7 × 0.24

Wd = 3.528 J

Workdone in stacking the 6th

• Weight (W) = 14.7 N
• Height (h) = 0.3 m
• Workdone (Wd) = ?

Wd = Weight × height

Wd = 14.7 × 0.3

Wd = 4.41 J

Workdone in stacking the 7th

• Weight (W) = 14.7 N
• Height (h) = 0.36 m
• Workdone (Wd) = ?

Wd = Weight × height

Wd = 14.7 × 0.36

Wd = 5.292 J

Workdone in stacking the 8th

• Weight (W) = 14.7 N
• Height (h) = 0.42 m
• Workdone (Wd) = ?

Wd = Weight × height

Wd = 14.7 × 0.42

Wd = 6.174 J

Workdone in stacking the 9th

• Weight (W) = 14.7 N
• Height (h) = 0.48 m
• Workdone (Wd) = ?

Wd = Weight × height

Wd = 14.7 × 0.48

Wd = 7.056 J

Workdone in stacking the 10th

• Weight (W) = 14.7 N
• Height (h) = 0.54 m
• Workdone (Wd) = ?

Wd = Weight × height

Wd = 14.7 × 0.54

Wd = 7.938 J

Total workdone = 0.882 + 1.764 + 2.646 + 3.528 + 4.41 + 5.292 + 6.174 + 7.056 + 7.938

Total workdone = 39.69 J

Learn more about workdone:

https://brainly.com/question/14667371

#SPJ1

Answer 2

The WEIGHT of each brick is (m g) = 14.7 Newtons

Work to lift each brick = (force x distance) = [14.7 x (distance lifted)] Joules

Place 2nd brick on top of the 1st:  lift 6cm,  (14.7N x .06m) = 0.882 J

Place 3rd brick on top of the 2nd:  lift 12cm,  (14.7N x .12m) = 1.764 J

Place 4th brick on top of the 3rd:  lift 18cm,  (14.7N x .18m) = 2.646 J

Place 5th brick on top of the 4th:  lift 24cm,  (14.7N x .24m) = 3.528 J

Place 6th brick on top of the 5th:  lift 30cm,  (14.7N x .3m) = 4.41 J

Place 7th brick on top of the 6th:  lift 36cm,  (14.7N x .36m) = 5.292 J

Place 8th brick on top of the 7th:  lift 42cm,  (14.7N x .42m) = 6.174 J

Place 9th brick on top of the 8th:  lift 48cm,  (14.7N x .48m) = 7.056 J

Place 10th brick on top of the 9th:  lift 54cm,  (14.7N x .54m) = 7.938 J

Total work to stackum (addum up)  = 39.7 Joules

____________________________________________

Way #2  (easier):

Weight of each brick = (mg) = 14.7 Newtons

Work to stack each one = (14.7N) x (distance lifted) Joules

Number of bricks to lift  =  9

AVERAGE distance to lift them = (1/2) (54cm + 6cm) = 30cm

Average work = (weight of each brick) x (average distance lifted)

Total work = (number of bricks) x (weight of each) x (average lift)

Total work = (9 bricks) x (14.7N) x (0.3m) = 39.69 Joules