Calculating Work done by the Earth and the work done by the Spring

In summary, a 0.091 kg mass is thrown vertically downward with a speed of 3.80 m/s. The work done by the Earth is -0.080262 Joules and the work done by the spring is unknown. To calculate the work, the formula F times displacement is used, with the sign depending on the direction of force and displacement. In part B, the net work done on the mass is needed to find the work done by the spring.
  • #1
Paul36
2
0

Homework Statement


A mass of 0.091 kg hangs from a vertical spring in the lab room. You pull down on the mass and throw it vertically downward. The speed of the mass just after leaving your hand is 3.80 m/s.

Homework Equations


(a) While the mass moves downward a distance of 0.09 m, how much work was done on the mass by the Earth? Include the appropriate sign.
Work done by Earth = ...Joules

(b) At the instant in part (a) when the mass has moved downward a distance of 0.09 m, the speed of the mass has decreased to 2.13 m/s. How much work was done on the mass by the spring? Include the appropriate sign.
Work done by spring = ...Joules

The Attempt at a Solution


To calculate Work I'm using the formula F times displacement
So for (a) I calculated:
0.09m X -9.8m/s/s X 0.091kg = -0.080262J
is that correct?
For part B I have no idea what to do?
Thanks if you can help.
 
Physics news on Phys.org
  • #2
Part B mainly requires for you to calculate the difference in the kinetic energy.
 
  • #3
Paul36 said:
To calculate Work I'm using the formula F times displacement
So for (a) I calculated:
0.09m X -9.8m/s/s X 0.091kg = -0.080262J
is that correct?
Except for the sign. What determines the sign of the work done is whether the force and displacement are in the same direction or not. If they are, the work done is positive.
For part B I have no idea what to do?
What's the net work done on the mass?
 

1. How do you calculate the work done by the Earth?

The work done by the Earth can be calculated using the formula W = F x d, where W is the work done, F is the force applied, and d is the distance over which the force is applied. In the case of the Earth, the force is the gravitational force and the distance is the displacement of an object due to gravity.

2. What is the work done by the Spring?

The work done by a spring can be calculated using the formula W = 1/2kx^2, where W is the work done, k is the spring constant, and x is the displacement of the spring from its equilibrium position. This formula applies to springs that follow Hooke's Law, which states that the force applied by a spring is directly proportional to its displacement.

3. How do you determine the direction of work for the Earth and the Spring?

The direction of work done by the Earth and the Spring can be determined by the direction of the force applied. If the force and displacement are in the same direction, the work done is positive. If they are in opposite directions, the work done is negative.

4. Can the work done by the Earth and the Spring be negative?

Yes, the work done by the Earth and the Spring can be negative if the force and displacement are in opposite directions. This means that the energy is being transferred from the object to the Earth or the spring, rather than being added to the object's kinetic or potential energy.

5. How does the work done by the Earth and the Spring affect an object?

The work done by the Earth and the Spring can affect an object by changing its kinetic or potential energy. If the work done is positive, the object's energy will increase. If it is negative, the object's energy will decrease. This can result in a change in the object's velocity or position.

Similar threads

Finding the work done by a block
    • Introductory Physics Homework Help
Replies
4
Views
1K
Work Done By a Spring's Restoring Force
    • Introductory Physics Homework Help
Replies
4
Views
767
Calculating the spring force constant K
    • Introductory Physics Homework Help
Replies
14
Views
346
Integral for work done leading to potential energy sign confusion
    • Introductory Physics Homework Help
Replies
5
Views
584
Work Pulley Problem with constant speed
    • Introductory Physics Homework Help
Replies
2
Views
211
Homework: Calculate the work done to accelrate a car
    • Introductory Physics Homework Help
Replies
1
Views
678
Work done during a collision -- Change in Kinetic Energy & change in Momentum
    • Introductory Physics Homework Help
Replies
1
Views
564
Work Done by Gravity and Tension in a Pulley System
    • Introductory Physics Homework Help
Replies
3
Views
1K
Work done by gravity and by a spring
    • Introductory Physics Homework Help
Replies
11
Views
2K
How to calculate the work done
    • Introductory Physics Homework Help
Replies
5
Views
2K

Hot Threads

Recent Insights

Back
Top