2300 Joules is used to lift a wheelbarrow through 4 meters up an inclined plane into a container.
Why does the man use more joules (3500 J) to push the wheelbarrow?
primarily friction loss, bearings heat up on axle where wheelbarrow wheel turns.
Okay , but if a block and tackle was used to lift an object why does it use less energy than actually pushing that object up?
It does? Not in my shipyard :) Block and tackle tends to have higher frictional losses than a wheelbarrow.
All methods do the same amount of "useful" work. That is the weight times 4 meters up. With your simple machines, wheels up ramps, blocks and tackles, you reduce the Force necessary. However you increase the distance through which the force must act (ramp length over height, length of line pulled through your blocks) and the work done is the force times the distance.
By the way, I am assuming that either way the man goes up into the container. If not then he has to move his own mass up, not only the wheelbarrow.
To understand why the man uses more joules (3500 J) to push the wheelbarrow, we need to consider a few factors. The work done to lift the wheelbarrow is calculated by multiplying the applied force (in this case, force applied by the man) by the distance over which the force is applied (in this case, the height the wheelbarrow is lifted).
In the case of lifting the wheelbarrow through 4 meters up an inclined plane, the work done is given as 2300 Joules. This means that the applied force multiplied by the distance gives the value of 2300 Joules.
Now, when the man pushes the wheelbarrow, the work done depends on several factors like the weight of the wheelbarrow, the surface on which it is being pushed, the frictional forces involved, and the distance over which the force is applied.
If the work done by the man pushing the wheelbarrow is 3500 Joules, it indicates that the force applied by the man multiplied by the distance over which the force is applied results in a higher value compared to lifting the wheelbarrow.
There are a few reasons why this could be the case:
1. Friction: Pushing the wheelbarrow on the ground involves overcoming frictional forces between the wheelbarrow and the ground surface. Friction opposes motion, and this resistance requires more force to overcome compared to just lifting the wheelbarrow vertically, where friction is typically not a significant factor.
2. Inclination: If the inclined plane has a steeper slope, it would require more force to push the wheelbarrow up the inclined surface compared to lifting it straight up. Additionally, the distance covered horizontally along the inclined plane may also contribute to the higher work done.
3. Weight: The weight of the wheelbarrow itself can play a role in requiring greater force to push it along. A heavier wheelbarrow would demand more work to move it, increasing the required force.
Therefore, it is possible that the combination of friction, inclination, and weight contributes to the man using more joules (3500 J) to push the wheelbarrow compared to lifting it through the same distance of 4 meters up an inclined plane into a container.