WORK2

​WORK DONE
NO WORK DONE

​WORK DONE
NO WORK DONE

​WHO LOSE ENERGY?
WHO GAIN ENERGY?

• ​Work is a way of transferring energy.

• Energy is the capacity to do work.

• When work is done BY an object it loses energy and when work is done ON an object it gains energy. Another concept related to work and energy is power.

Power is the rate of doing work or the rate of using energy.

In equation,

𝑃 = 𝑊𝑜𝑟𝑘 /𝑡𝑖𝑚𝑒    or

P = 𝐸𝑛𝑒𝑟𝑔𝑦 /𝑡𝑖𝑚e

Power is the rate of doing work or the rate of using energy.

In equation,

𝑃 = 𝑊𝑜𝑟𝑘 /𝑡𝑖𝑚𝑒    or

P = 𝐸𝑛𝑒𝑟𝑔𝑦 /𝑡𝑖𝑚e

The conversion of unit from joules per second to watts is:

1 𝑤𝑎𝑡𝑡 = 1 𝑗𝑜𝑢𝑙𝑒 /1 𝑠𝑒𝑐𝑜𝑛d

Power(watts)

​Sample problem:

What is the power output of the stickman that pushes the box 5 meters in 3 seconds with a constant force of 12 N?

​Sample problem:

What is the power output of the stickman that pushes the box 5 meters in 3 seconds with a constant force of 12 N?

Given:

5 m= d

3 s= t

12N=F

​Sample problem:

What is the power output of the stickman that pushes the box 5 meters in 3 seconds with a constant force of 12 N?

Given:

5 m= d

3 s= t

12N=F

Find:

W=?

​Sample problem:

What is the power output of the stickman that pushes the box 5 meters in 3 seconds with a constant force of 12 N?

Given:

5 m= d

3 s= t

12N=F

Find:

W=?

Formula:

P= W/t

Final answer:

P=20 watts

Solution:

P=W/t

P=Fd/t

P=12N(5m)/3s

P=20Nm/s

​Sample problem:

What is the power output of the stickman that pushes the box 5 meters in 3 seconds with a constant force of 12 N?

Given:

5 m= d

3 s= t

12N=F

Find:

W=?

​Formula: P= W/t Solution: P=W/t P=Fd/t P=12N(5m)/3s P=20Nm/s Final answer: P=20 watts

Draw

What is the power output if 15N of force was applied on an object at an angle of 25° above the horizon to move an object 4meters horizontally in 4 seconds.