Answer:
The gravitational potential energy equals the work needed to lift the object.
Explanation:
here we know that

work done is given as

Potential energy is given as

force due to gravity is given as

now here if we plug in the value of distance and force in the formula of work done then we will have

so here we got

so we can concluded that
The gravitational potential energy equals the work needed to lift the object.
Answer: 580 N
Refer to attached figure.
The angle of inclination is 22 degrees
weight (gravitational force) acts downwards.
Normal force is a contact force which acts perpendicular to the point of contact.
The horizontal component (mg cos 22 ) balances the normal force and the vertical component balances the frictional force.
Gravitational force on an object = mg
The normal force 

The force tending to lift the load (vertical force) is equal to <u>22.5N.</u>
Why?
Since the boy is pulling a load (150N) with a string inclined at an angle of 30° to the horizontal, the total force will have two components (horizontal and vertical component), but we need to consider the given information about the tension of the string which is equal to 105N.
We can calculate the vertical force using the following formula:

Hence, we can see that <u>the force tending to lift the load</u> off the ground (vertical force) is equal to <u>22.5N.</u>
Have a nice day!
All the weight of the wooden board is bear by the support located at the centre of the rod, and the other support which is located at the end, will have no reaction force, or 0 reaction force.
Therefore the reaction at the centre support is equal to the weight of the board, while the support at the end has 0 reaction force.