Log In Start studying!

Select your language

Suggested languages for you:
Answers without the blur. Sign up and see all textbooks for free! Illustration

Q21PE

Expert-verified
College Physics (Urone)
Found in: Page 317

Answers without the blur.

Just sign up for free and you're in.

Illustration

Short Answer

(a) What is the mechanical advantage of a wheelbarrow, such as the one in Figure \({\rm{9}}{\rm{.24}}\), if the center of gravity of the wheelbarrow and its load has a perpendicular lever arm of \({\rm{5}}{\rm{.50}}\;{\rm{cm}}\), while the hands have a perpendicular lever arm of \({\rm{1}}{\rm{.02}}\;{\rm{m}}\)? (b) What upward force should you exert to support the wheelbarrow and its load if their combined mass is\({\rm{55}}{\rm{.0}}\;{\rm{kg}}\)? (c) What force does the wheel exert on the ground?

  1. The mechanical advantage is\({\rm{18}}{\rm{.5}}\).
  2. The upward force is\({\rm{29}}{\rm{.1}}\;{\rm{N}}\).
  3. The force exerted by the wheel on the ground is\({\rm{509}}{\rm{.25}}\;{\rm{N}}\).
See the step by step solution

Step by Step Solution

Step 1: Idea of equilibrium under Forces

For the equilibrium under several forces the upward forces are equal to the downward forces.

Step 2: Diagram

The center of gravity of the wheelbarrow and its load has a perpendicular lever arm of \({\rm{5}}{\rm{.50}}\;{\rm{cm}}\), while the hands have a perpendicular lever arm of \({\rm{1}}{\rm{.02}}\;{\rm{m}}\).

The free body diagram is as shown below:

Step 3: Calculation of the mechanical advantage of the wheelbarrow

  1. The mechanical advantage is,

\(\begin{align}{\rm{MA = }}\frac{{{\rm{1}}{\rm{.02}}}}{{{\rm{5}}{\rm{.50 \times 1}}{{\rm{0}}^{{\rm{ - 2}}}}}}\\{\rm{ = 18}}{\rm{.5}}\end{align}\)

Hence, the value is \({\rm{18}}{\rm{.5}}\).

Step 4: Calculation of the upward force

b. We know, mechanical advantage is,

\({\rm{MA = }}\frac{{{\rm{mg}}}}{{{{\rm{F}}_{\rm{i}}}}}\)

For,\({\rm{mg = 55}}{\rm{.0 \times 9}}{\rm{.8}}\),

\(\begin{align}{{\rm{F}}_{\rm{i}}}{\rm{ = }}\frac{{{\rm{55}}{\rm{.0 \times 9}}{\rm{.8}}}}{{{\rm{18}}{\rm{.5}}}}\\{\rm{ = 29}}{\rm{.1}}\;{\rm{N}}\end{align}\)

Hence, the upward force is \({\rm{29}}{\rm{.1}}\;{\rm{N}}\).

Step 5: Calculation of the force by the wheel on the ground

c. The force exerted by the wheel on the ground is,

\(\begin{align}{\rm{N}}{{\rm{l}}_{\rm{o}}}{\rm{ = }}{{\rm{F}}_{\rm{i}}}\left( {{{\rm{l}}_{\rm{i}}}{\rm{ - }}{{\rm{l}}_{\rm{o}}}} \right)\\{\rm{N = }}\frac{{{{\rm{F}}_{\rm{i}}}\left( {{{\rm{l}}_{\rm{i}}}{\rm{ - }}{{\rm{l}}_{\rm{o}}}} \right)}}{{{{\rm{l}}_{\rm{o}}}}}\\{\rm{N = }}{{\rm{F}}_{\rm{i}}}\left( {{\rm{MA - 1}}} \right)\end{align}\)

Substituting the values we get,

\(\begin{align}{\rm{N = 29}}{\rm{.1}}\left( {{\rm{18}}{\rm{.5 - 1}}} \right)\\{\rm{ = 509}}{\rm{.25}}\;{\rm{N}}\end{align}\)

Hence, the force is \({\rm{509}}{\rm{.25}}\;{\rm{N}}\).

Recommended explanations on Physics Textbooks

94% of StudySmarter users get better grades.

Sign up for free
94% of StudySmarter users get better grades.