To calculate the unbalanced force on the object, we need to subtract the frictional force from the applied force:
Unbalanced force = Applied force - Frictional force
Unbalanced force = 50. N - 15. N
Unbalanced force = 35. N
To calculate the acceleration of the object, we can use Newton's second law:
Fnet = ma
35. N = 10. kg * a
a = 3.5 m/s^2
Therefore, the unbalanced force on the object is 35. N and the acceleration of the object is 3.5 m/s^2.
Something seems to be wrong here: Fnet > ma! But we know from Newton’s second law that ma must equal the unbalanced force (Fnet ). In this situation, Fnet is equal to 15 newtons (5.0 kg · 3.0 m/s 2 ), not to the applied force of 20. newtons. Where have 5.0 newtons gone? There is another force present that we have not considered: friction. Frictional forces are always present when two surfaces are in contact. The direction of a frictional force on an object is always opposite to the direction of the object’s motion. We will represent a frictional force by the symbol Ff . We now complete the diagram above by adding in the 5.0-newton frictional force: 9. A force of 50. newtons is used to drag a 10.-kilogram object across a horizontal table. If a frictional force of 15. newtons is present on the object, calculate (a) the unbalanced force on the object and (b) the acceleration of the object.
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