Calculating Work Done on Child & Sled Pulled by Force

In summary, a child on a sled with a combined mass of 47.0 kg is pulled by a 100.00 N force at a 45 degree angle with the horizontal axis. The force of friction acting on the sled is 30.0 N. When pulled a distance of 10.0 m, the total work done on the child and sled is 707 Joules. This is calculated by using the formula W=F(costheta) . deltad. To calculate the final speed at the end of 10.0 m, use the formula W= (1/2)mv^2 and rearrange it to solve for v.
  • #1
fa08ti
32
0
A child on a sled (having a combined mass of 47.0 kg) is pulled by a force directed along a rope that makes a 45 degree angle with the horizontal axis. the force exerted on the rope is 100.00 N. the force of friction acting on the sled is 30.0 N. if the child is pulled a distance of 10.0 m along a level field, determine the total work done on the child and the sled.

Attempt:
Given:
d: 10.0 m, F:100.0 N (45 degrees), Ff: 30.0 N (180 Degrees)

W=F(costheta) . deltad
W= 100.00 N X cos45 X 10.0m
W=707J
that would be just for the rope

would i have to do the same calculation using the Ff now? then add both numbers to get total work done?

It also asks for the final speed at the end of 10.0 m

HELP PLEASE!
 
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  • #2
fa08ti said:
would i have to do the same calculation using the Ff now? then add both numbers to get total work done?
Yes.

It also asks for the final speed at the end of 10.0 m
Make use of the net work done that you've calculated.
 
  • #3
ok so for the speed, i'd use
W= (1/2)mv^2 and just rearrange it
 
Last edited:
  • #4
fa08ti said:
ok so for the speed, i'd use
W= (1/2)mv^2 and just rearrange it
Good!
 
  • #5
thanks sooooo much. I've never taken physics before and I'm finding that while i understand most concepts, I tend to need a lot of reassurance
 

1. How do you calculate the work done on a child and sled pulled by a force?

The work done on a child and sled can be calculated by multiplying the force applied to the sled by the distance the sled is pulled. This is represented by the equation W = Fd, where W is work, F is force, and d is distance.

2. What units are used to measure work?

The SI unit for work is the joule (J). However, in some cases, other units such as foot-pounds (ft-lb) or calories (cal) may be used.

3. Can the work done on a child and sled be negative?

Yes, the work done on a child and sled can be negative if the force applied is in the opposite direction of the movement of the sled. This indicates that the force is doing work against the motion of the sled, resulting in a decrease in its kinetic energy.

4. How does the angle of the force affect the work done on the child and sled?

The angle of the force applied to the sled affects the work done by changing the component of the force in the direction of the sled's movement. The work done is maximized when the force is applied in the same direction as the sled's movement, and minimized when the force is perpendicular to the sled's movement.

5. Can you calculate the work done on a child and sled without knowing the force applied?

No, the work done on a child and sled cannot be calculated without knowing the applied force. In order to calculate work, both the magnitude and direction of the force must be known. If only the distance and direction of movement are given, the work done can be estimated but not accurately calculated.

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