Question 64: Work, Energy and Power & Circular Motion

Question

A block of mass $$100 \mathrm{~kg}$$ slides over a distance of $$10 \mathrm{~m}$$ on a horizontal surface. If the co-efficient of friction between the surfaces is 0.4, then the work done against friction $$(\operatorname{in} J$$) is :

Accepted Answer

$$\begin{aligned}
& 	ext { Given } \mathrm{m}=100 \mathrm{~kg} \
& \mathrm{~s}=10 \mathrm{~m} \
& \mu=0.4 \
& 	ext { As } \mathrm{f}=\mu \mathrm{mg}=0.4 	imes 100 	imes 10=400 \mathrm{~N} \
& 	ext { Now } \mathrm{W}=\mathrm{f} . \mathrm{s}=400 	imes 10=4000 \mathrm{~J}
\end{aligned}$$

Answer

3900

Answer

4500

Answer

4200

Answer

4000

Work, Energy and Power & Circular Motion

A block of mass $100 \mathrm{~kg} slides over a distance of 10 \mathrm{~m} on a horizontal surface. If the co-efficient of friction between the surfaces is 0.4, then the work done against friction (\operatorname{in} J$) is :

Choose the correct answer: