Question

If force F is increasing with time and at t = 0, F = 0, where will slipping first start?

• A. between 3 kg and 2 kg
• B. between 2 kg and 1 kg
• C. between 1 kg and ground
• D. Both (a) and (b)

Answer 1

The correct option is C between 1 kg and ground

Minimum force required for slipping to occur between 3kg and 2kg =$\mu N_1=0.5\times 30=15N$

Minimum force required for slipping to occur between 2kg and 1kg =$\mu N_1=0.3\times (30+20)=15N$

Minimum force required for slipping to occur between 1kg and ground =$\mu N_1=0.1\times (30+20+10)=6N$

Thus slipping takes place first at the surface for which minimum force required is least. Thus slipping starts between 1kg block and ground.