# Forces: Wedge and Block Problem + Pulley System Problem

• akemi3
In summary, for question 9), to keep the block from sliding up or down the wedge, the horizontal acceleration of the wedge and the block must be equal. The equation mgsin18° = m1ax can be used to solve for the horizontal acceleration. For question 10), to find the tension, an equilibrium statement of forces up and forces down must be written for each block. This may seem complicated, but it is important to consider the forces acting on each block separately.
akemi3

## Homework Statement

9) A 15 kg wedge is pushed along a frictionless surface. There is no friction between the wedge and the block. What force, F, is required to keep the block from sliding up or down the wedge?

See attachment for diagram.

10) Find the tension, T.

See attachment for diagram.

ƩF=ma

## The Attempt at a Solution

9) So I know that in order for the block to not slide, the horizontal acceleration for both the wedge and the block have to be equal. To solve for the horizontal acceleration I used the horizontal component of block (m1) (where the xy axis is tilted).

mgsin18° = m1ax

I don't really know where to go from there because I do not feel that I am on the right track.

10) All I have figured out is if all three blocks were to be laid out on a flat surface, the three blocks would all move in one direction. I am unsure about what I'm supposed to do with all the pulleys. I was wondering if all I really needed to do was to focus on one block (the 20N one?). I am admittedly overwhelmed by how many pulleys there are.

#### Attachments

• wedge and block.jpg
44.8 KB · Views: 809
• pulleys.jpg
34.9 KB · Views: 854
For question 9) remembering that only the wedge will experience the force F, and therefore the acceleration. Since the wedge/block interface is smooth if F was very large the block would simply slide up until it fell of the top.

So you could equally consider the acceleration to be in the opposing direction, just for the block. Try drawing the block, with the acceleration from the wedge, and gravity.For question 10) I assume this is supposed to be equilibrium, in which case the forces must balance. So write an equilibrium statement of forces up and forces down. I think this is designed to look scary

## 1. How do I calculate the forces on a wedge?

To calculate the forces on a wedge, you can use the equation F = μN, where F is the force exerted on the wedge, μ is the coefficient of friction, and N is the normal force. You can also use trigonometry to break down the forces into their horizontal and vertical components.

## 2. What is the relationship between the angle of a wedge and the effort force required?

The relationship between the angle of a wedge and the effort force required is inverse. This means that as the angle of the wedge increases, the effort force required to move it decreases. This is because a larger angle creates a smaller surface area for the object to be pushed against, making it easier to move.

## 3. How can I determine the mechanical advantage of a pulley system?

The mechanical advantage of a pulley system can be determined by counting the number of ropes supporting the load. Each supporting rope will decrease the effort force required by a certain amount, depending on the type of pulley system. For example, a single fixed pulley has a mechanical advantage of 1, while a compound pulley system can have a mechanical advantage of 2 or more.

## 4. What is the difference between a wedge and a block?

A wedge is a simple machine that is used to lift or move objects by applying a force to the wedge, while a block is an object that can be used as a weight or support. In terms of forces, a wedge converts a downward force into a horizontal force, while a block typically experiences both a vertical and horizontal force.

## 5. How does friction affect the movement of a block on a surface?

Friction can greatly affect the movement of a block on a surface. The coefficient of friction between the block and the surface will determine how much force is required to move the block, and can also impact the speed and direction of the block's movement. Additionally, friction can also cause wear and tear on the block and the surface, leading to decreased efficiency and potential damage.

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