A 1.7kg book is lying on a 0.80m -high table. You pick it up and place it on a bookshelf 2.3m above the floor.

You are watching: During this process, how much work does your hand do on the book?

A) During this process, how much work does gravity do on the book?

B) During this process, how much work does your hand do on the book?

(A) The expression to calculate the work done is, $W=F \cdot d \cos \theta$When the book is picked up and placed on a book shelf, the distance is equal to the difference of the heights.

\begin{aligned}d=2.3 \mathrm{~m}-0.80 \mathrm{~m} \\=1.50 \mathrm{~m}\end{aligned}The force is calculated as follows:

F=m g

Here, \mathrm{m} is the mass, \mathrm{g} is the gravity, and \mathrm{F}0 is the weight force.

Substitute 1.7 \mathrm{~kg} for \mathrm{m} and 9.8 \mathrm{~m} / \mathrm{s}^{2} for \mathrm{g} in expression F=m g.

\begin{aligned}F=(1.7 \mathrm{~kg})\left(9.8 \mathrm{~m} / \mathrm{s}^{2}\right) \\=16.67 \mathrm{~N}\end{aligned}Substitute 16.66 \mathrm{~N} for \mathrm{F}, 1.50 \mathrm{~m} for \mathrm{d}, and 180^{\circ} for \theta in expression W=F \cdot d \cos \theta \mathrm{v}

\begin{aligned}W=(16.67 \mathrm{~N})(1.50 \mathrm{~m}) \cos 180^{\circ} \\=-25.0 \mathrm{~J}\end{aligned}Part A The work done by the gravity on the book is -25.0 \mathrm{~J}.

(B) The force is calculated as follows:

F=m g

Here, m is the mass, g is the gravity, and F is the weight force.

Substitute 1.7 \mathrm{~kg} for \mathrm{m} and -9.8 \mathrm{~m} / \mathrm{s}^{2} for g in expression F=m g.

\begin{aligned}F=(1.7 \mathrm{~kg})\left(-9.8 \mathrm{~m} / \mathrm{s}^{2}\right) \\=-16.67 \mathrm{~N}\end{aligned}Substitute -16.67 \mathrm{~N} for \mathrm{F}, 1.50 \mathrm{~m} for \mathrm{d}, and 180^{\circ} for \theta in expression W=\vec{F} \cdot d \cos \theta.

\begin{aligned}W=(-16.67 \mathrm{~N})(1.50 \mathrm{~m}) \cos 180^{\circ} \\=25.0 \mathrm{~J}\end{aligned}Part B The work done by the hand on the book is 25.0 \mathrm{~J}.

See more: Sometimes I Wonder Why I Even Bother, #Sometimes I Wonder Why I Bother On Tumblr

Hottest videos

Comment

Name *

Email *

Website

Save my name, email, and website in this browser for the next time I comment.

Δ

Related Posts
Q&A
which is larger 10 km or 1000 cm?
November 11, 2021 thanh
Q&A
can i still drink on all theses medactions?
November 11, 2021 thanh
Search for: