A construction worker uses an electrical device to attract fallen nails and sharp objects from a construction site. What is caus
1 answer:
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Answer:
<h2>15.25 N</h2>Explanation:
A force of is acting on a wagon along the road. The wagon weights
. Acceleration of the wagon is given as
.
Consider the block as the system, the forces acting are Frictional force, Gravitational force, Normal reaction and External force applied by us.
Gravitational Force and Normal Reaction cancel out each other.
Net External Force = Mass of system/wagon Acceleration of wagon
has a negative sign because it opposes the motion of the wagon.
∴ Frictional Force = 15.25 N
Answer:
θ = 13.7º
Explanation:
- According to the work-energy theorem, the change in the kinetic energy of the combined mass of the child and the sled, is equal to the total work done on the object by external forces.
- The external forces capable to do work on the combination of child +sled, are the friction force (opposing to the displacement), and the component of the weight parallel to the slide.
- As this last work is just equal to the change in the gravitational potential energy (with opposite sign) , we can write the following equation:
- ΔK, is the change in kinetic energy, as follows:
- ΔU, is the change in the gravitational potential energy.
- If we choose as our zero reference level, the bottom of the slope, the change in gravitational potential energy will be as follows:
- Finally, the work done for non-conservative forces, is the work done by the friction force, along the slope, as follows:
- Replacing (2), (3), and (4) in (1), simplifying common terms, and rearranging, we have:
- Replacing by the givens and the knowns, we can solve for sin θ, as follows:
⇒ θ = sin⁻¹ (0.236) = 13.7º