MCQ
A heavy box is solid across a rough floor with an initial speed of $4 \,m / s$. It stops moving after $8$ seconds. If the average resisting force of friction is $10 \,N$, the mass of the box (in $kg$ ) is .....
- A$40$
- ✓$20$
- C$5$
- D$2.5$
✓
Answer
Correct option: B.
$20$
b
(b)
(b)
Same like previous question
$\mu=\frac{4}{80}=0.05$
$F=\mu m g$
$10=0.5 \,m$
$m=20 \,kg$
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