Did This Student Calculate the Physics Homework Correctly?

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SUMMARY

The discussion focuses on calculating the forces involved in two physics problems related to friction and acceleration. For the first problem, the force of sliding friction is calculated as 1097.6 N, leading to a net force of 102.4 N on the tree and an acceleration of 0.32 m/s². The second problem involves a sled being pulled at an angle, with the coefficients of kinetic and static friction provided. The calculations utilize Newton's second law and the relationship between normal force and weight to derive the necessary values.

PREREQUISITES
  • Understanding of Newton's laws of motion
  • Knowledge of friction coefficients (static and kinetic)
  • Ability to calculate normal force from mass and gravitational acceleration
  • Familiarity with vector components in physics (forces at angles)
NEXT STEPS
  • Study the concept of normal force in different scenarios
  • Learn about the effects of angles on tension and friction in physics problems
  • Explore advanced applications of Newton's laws in real-world scenarios
  • Investigate the differences between static and kinetic friction in various materials
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Students studying physics, educators teaching mechanics, and anyone interested in understanding the principles of force, friction, and acceleration in practical applications.

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Homework Statement



A tractor exters a force of 1200N to pull a fallen tree to pull a fallen tree along the ground. If the tree has a mass of 320KG and the coefficient of sliding friction is 0.35, find
a. the force of sliding friction
b. the netforce on the tree
c. the acceleration of the tree

Note:In case of sliding friction, if the force applied to a body is greater than the force needed to overcome friciton, there is acceleration.

Two children are pulled on a sled over snow-covered ground. The sled which is initially at rest, is pulled by a rope that makes an angle of 40 degrees with the horizontal. The children have combined mass of 45 kg and the sled has a mass of 5kg. The coefficient of kinetic and static friction are U(k)=0.15 and U(s)= 0.2 . Find the frictional force exerted by the grounf on the sled and the acceleration of the children and sled, starting from rest, if the tension in the rope is a)100N b)140N


Homework Equations



Forces in the x direction is Fx: 1200 - friction = ma


The Attempt at a Solution


I think the force of sliding friction would be

1097.6

Acceleration of tree is .32m/s

force of sliding friction is the coefficient * Normal force

You can find normal force because Fy: N - Weight of tree = 0 That is the forces in the y direction.
N = weight of the tree and weight of the tree is mass times gravity.

N* .35 = 1097.6


Forces in the x direction is Fx: 1200 - friction = ma
1200-1097.6 = 320a
a = (1200-1097.6)/320
a = .32

I hope that's right >_>
 
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