High School Physics : Understanding Work
Study concepts, example questions & explanations for High School Physics
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Example Questions
Example Question #1 : Work
A bodybuilder lifts a 
Work is a vector quantity equal to the change in energy in a given direction. Our net work will be equal to product of force and displacement.
We can write this equation in terms of Newton's second law to incorporate our given values.
During its motion the weight travels a distance of 
The total work will be zero because there was no net displacement.
Example Question #1 : Work
A 
Velocity
Power
Time
Acceleration
Potential energy
Acceleration
The formula for work is 
Since 
The problem gives us the mass and the distance traveled, but not the acceleration. Given the acceleration, along with the mass and distance, we would be able to calculate the work.
Example Question #61 : Energy And Work
Miguel pushes a crate with 
Time
Velocity
Energy
Acceleration
Distance
Distance
The formula for work is 
The problem gives us the mass, but is missing the distance. Given the distance, we would be able to calculate the work.
Example Question #1 : Work
Which of the following is an example of work?
A man sits in a chair.
A skier skies down a frictionless hill with no loss in kinetic energy.
A weightlifter lifts a heavy barbell above his head.
A student types numerous essays for class.
A car drives along the road at a constant speed.
A weightlifter lifts a heavy barbell above his head.
Work is a force times a distance or 
Only one of these has a force times a distance: the weightlifter lifting a weight above his head.
The car moving at a constant velocity has no acceleration and therefore no force.
Typing essays does not require a force times a distance (though it sure feels like work!).
If the skier has no loss in energy, then no work was done, as work is also the measurement of the change in energy.
The man sitting in a chair has a constant velocity of zero, no acceleration, and therefore no force.
Example Question #62 : Energy And Work
Which of these is a correct formula for work?
Work is produced when a force is used to create a change in distance. The amount of work is given by the product of the distance traveled and the force applied.
Example Question #4 : Work
Michael pushes a box 
We need to know the force used to find the work
We need to know the time to find the work
We need to know the mass of the box to find the work
Works is equal to force times distance:
Since the box moves with a constant velocity, it has no acceleration. Remember that 
If there is no net force, then there is also no work.
Example Question #7 : Work
Rodrigo pushes a sofa 
We need to know the coefficient of friction of the sofa on the floor to solve
We need to know the mass of the sofa to solve
Work is the product of a net force over a given distance.
In order for there to be work, there must be a net force applied and the object must have a non-zero displacement. In this question we are given the displacement, but we have to solve for the force.
The question only tells us that the couch moves with constant velocity. This tells us that acceleration is zero. If acceleration is zero, then force must also be zero according to Newton's second law.
If the force is zero, then the work is also zero.
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