The block starts from rest as shown in the fi | vedclass

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Question

(A) Given, applied force, $F=10 \,N$.Mass of the block, $m=2 \,kg$.Coefficient of kinetic friction, $\mu=0.2$.Normal force, $N=mg=2 	imes 10=20 \,N$.

Vedclass · Accepted Answer

$240 \,J, -96 \,J$

Vedclass · Answer

(A) Given, applied force, $F=10 \,N$.Mass of the block, $m=2 \,kg$.Coefficient of kinetic friction, $\mu=0.2$.Normal force, $N=mg=2 	imes 10=20 \,N$.Friction force, $f=\mu N=0.2 	imes 20=4 \,N$.Net force, $F_{	ext{net}}=F-f=10-4=6 \,N$.Acceleration, $a=\frac{F_{	ext{net}}}{m}=\frac{6}{2}=3 \,m/s^2$.Distance covered in $t=4 \,s$ starting from rest $(u=0)$:$s=ut+\frac{1}{2}at^2=0+\frac{1}{2} 	imes 3 	imes (4)^2=24 \,m$.Work done by the applied force of $10 \,N$ $(W_1)$:$W_1=F 	imes s=10 	imes 24=240 \,J$.Work done by the friction force of $4 \,N$ $(W_2)$:$W_2=f 	imes s 	imes \cos(180^{\circ})=-4 	imes 24=-96 \,J$.

The block starts from rest as shown in the figure. Find the work done by the force of $10 \,N$ and friction in the time $0$ to $4 \,s$. [Take, $g=10 \,m/s^2$]

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