226k views
3 votes
A 8 kg object is pulled horizontally in a straight line for 10 meters. If the coefficient of kinetic friction between the object and surface is 0.4, how much work is done by friction? (Remember the directions of displacement and frictional force.) J

User Innominate
by
5.4k points

1 Answer

4 votes

Answer:


W=320J

Step-by-step explanation: We need to find the total work that an object weighing 8kg does due to frictional force, the coefficient of kinetic friction is 0.4 and the object is pulled for 10 meters, the frictional force would be as follows:


\begin{gathered} F_k=\mu N \\ \mu=0.4 \\ N=\text{ Normal force} \\ N=(8\operatorname{kg})*(10ms^(-2))=80N \\ \therefore\Rightarrow \\ F_k=(0.4)*(8\operatorname{kg})*(10ms^(-2))=32N \\ \\ \end{gathered}

Therefore the total work done due to frictional forces is simply as follows:


\begin{gathered} W=F_k\cdot d\cdot\cos (\theta)\rightarrow\theta=0 \\ \therefore\Rightarrow \\ W=(32N)*(10m)=320J \\ W=320J \end{gathered}

User BretC
by
5.5k points