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3 years ago

when a book falls from a shelf to the ground without anyone pushing on it, no work is done to the book. True or False

Physics

1 answer:

VikaD [51]3 years ago

8 0

That's false.

-- The force on the book is its weight.

-- The force acts through the distance the book falls.

-- The work done on the book is

(weight) x (length of the fall)

-- Gravity DOES the work.

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Density of copper is 8.96 g/cm3and density of zinc is 7.14 g/cm3. Brass is an alloy made of copper and zinc. You are given a sam

kvasek [131]

Answer:

The material cost for making one ton of the brass sample that I have is $8149.04.

Explanation:

Density of copper = 8.96 g/cm^3 = 8.96×10^-3 kg/cm^3

Price of copper = $6.13/kg

Price of copper per volume = 8.96×10^-3 kg/cm^3 × $6.13/kg = $0.0549/cm^3

Density of zinc = 7.14 g/cm^3 = 7.14×10^-3 kg/cm^3

Price of zinc = $1.8/kg

Price of zinc per volume = 7.14×10^-3 kg/cm^3 × $1.8/kg = $0.0129/cm^3

Price of brass per volume = 0.0549 + 0.0129 = $0.0678/cm^3

Density of brass I have is 8.32 g/cm^3 = 8.32 g/cm^3 × 1 kg/1000 g × 1 ton/1000 kg = 8.32×10^-6 ton/cm^3

Price = $0.0678/cm^3 ÷ 8.32×10^-6 ton/cm^3 = $8149.04/ton

5 0

3 years ago

Read 2 more answers

The wheel of a stationary exercise bicycle at your gym makes one rotation in 0.670 s. Consider two points on this wheel: Point P

defon

Answer:

0.938 m/s.

Explanation:

Given:

ω = 1 rev in 0.67 s

In rad/s,

1 rev = 2pi rad

ω = 2pi ÷ 0.67

= 9.38 rad/s

Rp = 10 cm

= 0.1 m

V = ω × r

= 9.38 × 0.1

= 0.938 m/s.

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