Work and transformation of energy

In summary, the conversation discusses various problems related to work and energy in a physics course. The solutions to these problems involve calculating the work done, explaining transformations of energy, and applying equations such as W = F x D cos(theta). The conversation also includes a discussion on the conditions for work and potential energy. The person seeking help is commended for their understanding of the subject.
  • #1
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Homework Statement


Hi I am taking a grade 11 physics correspondance course and would like to know if iam on the right track. thanks in advance.

1. (a) A force of 280 N is required to push a box 8.2 m across a rough floor. How much work is done?

(b) Explain 1 transformation of energy that occurred in part a.


(e) It is found that 1.50 X 10 ^3 J of work are required to push a box across a floor a horizontal distance of 8.0 m . What average force is being exerted on the box?

Homework Equations


W = F X D



The Attempt at a Solution



(a) W= F X D
=280 N X 8.2 m
=2296 J
=2.2 X 10 ^3

(b) A force is provding energy that will be everntually transformed into heat energy through friciton between the force and the rough floor. The force is acting against the force of friciton.

(c) there is no work being done. This is becuase conditions for work are quite specfic and in this problem a displacement occurs but the force being exerted does not cause the displacement.

(d) W = F X D cos (theta)
=104 n X 5.0 m X cos 32 degrees
=440.99 J
=441 J

(e) F = W/ D
=150 J / 8.0 m = 18.75 N
Thanks
Pharm 89

 
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  • #2
Just so you know, there are answers you posted for questions that you didn't provide, so I can't really help you with those. But you seem to know what your doing otherwise. Nice Job!
 
  • #3
G01 said:
Just so you know, there are answers you posted for questions that you didn't provide, so I can't really help you with those. But you seem to know what your doing otherwise. Nice Job!

whoops question c and d

(c) A 46 kg woman climbs a flight of stairs, 6.2 m high. How much work does she do.

(d) A force of 104 N is applied to a 26 kg mass at an angle of 32 degrees to the horizontal. Calculate the work done when the mass is moved through a horizontal distance of 5.0m .

Thanks
Pharm89
 
  • #4
pharm89 said:
whoops question c and d

(c) A 46 kg woman climbs a flight of stairs, 6.2 m high. How much work does she do.

(d) A force of 104 N is applied to a 26 kg mass at an angle of 32 degrees to the horizontal. Calculate the work done when the mass is moved through a horizontal distance of 5.0m .

Thanks
Pharm89
For problem (c), what is the change in the person's energy at the top of the stairs, and how would you account for that change?
 
  • #5
c. To lift an object, even yourself, you must exert an upward force equal to the the object's weight. Here the woman must exert an upward force of 46kg* g= 46*9.81 Newtons for an upward distance of 6.2 m.

PhantomJay is suggesting looking at the change in potential energy but you may not have had that.

The other problems look good.
 
  • #6
HallsofIvy said:
c. To lift an object, even yourself, you must exert an upward force equal to the the object's weight. Here the woman must exert an upward force of 46kg* g= 46*9.81 Newtons for an upward distance of 6.2 m.

PhantomJay is suggesting looking at the change in potential energy but you may not have had that.

The other problems look good.

Thanks for the help.

therefore the conditions for work are met.
g= 46kg X 9.8 N
=450.8 N
W=450.8 N X 6.2 m
W=2794.96 J = 2795 J
 

1. What is work and how is it related to energy?

Work is defined as the transfer of energy from one object to another by applying a force. Energy is the ability to do work, so work and energy are closely related. When work is done on an object, its energy changes.

2. What is the formula for calculating work?

The formula for calculating work is W = F x d, where W is work, F is force, and d is distance. This means that work is equal to the force applied to an object multiplied by the distance the object moves in the direction of the force.

3. What is the relationship between work and power?

Power is the rate at which work is done. It is calculated by dividing work by time. The more work that is done in a given amount of time, the more power is required. Therefore, work and power are directly related.

4. How is energy transformed from one form to another?

Energy can be transformed from one form to another through various processes such as mechanical work, thermal energy transfer, and electromagnetic radiation. For example, when a person rides a bike, their muscles convert chemical energy into mechanical energy to move the pedals, and the bike's wheels then convert this mechanical energy into kinetic energy.

5. What are some examples of energy transformation in everyday life?

Energy transformation occurs in many everyday activities. Some common examples include using electrical energy to power appliances, burning fuels to produce heat and light, and using chemical energy to power cars and other vehicles. Even the food we eat is a form of energy that our bodies transform into mechanical energy for movement and other bodily functions.

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