A) What is the advantage of class 3 lever? (1 point)

Question

It decreases the amount of force that needs to be applied.
It decreases the distance over which force needs to be applied.
It decreases the amount of work that needs to be done.
It increases the mechanical advantage compared with other levers.
A) Gardeners would need to use 960 Newtons of force to lift a potted tree 45 centimeters onto a
deck. Instead, they set up a lever. If they press the lever down 2 meters, how much force do they
use to lift the tree? (1 point)
216 N
21,600 N
432 N
1,920 N

Answer 1

A) The advantage of a class 3 lever is that it increases the distance over which force needs to be applied. Class 3 levers require more force to lift the load than the load's weight but allow for a greater distance to be moved.

B) To solve for the force used when the gardeners press the lever down:

Using the principle of levers (Mechanical Advantage), we know:

\[ \text{Load} \times \text{Load Distance} = \text{Effort} \times \text{Effort Distance} \]

Let:

• Load = 960 N (weight of the tree)
• Load Distance = 45 cm (0.45 m)
• Effort Distance = 2 m

We need to find the Effort.

\[ 960 , \text{N} \times 0.45 , \text{m} = \text{Effort} \times 2 , \text{m} \]

Calculating the left side:

\[ 960 \times 0.45 = 432 , \text{N m} \]

Now substituting into the equation:

\[ 432 = \text{Effort} \times 2 \]

To find Effort, divide both sides by 2:

\[ \text{Effort} = \frac{432}{2} = 216 , \text{N} \]

So, the force the gardeners would use to lift the tree is 216 N.