Question

box of mass 20 kg is connected to mass of 2 kg (hanging) through a light string and an ideal pulley as shown in figure. Coefficient of kinetic friction between box and surface is 0.05. What is acceleration of the box? (g = 10 m/s2)

Answer 1

Answer:

As the string is inextensible, and the pulley is smooth, therefore both the 2kg block and the 20kg trolley have the same acceleration a.

Let T be tension in the string.

The equation of motion of the block is

40−T=2a …(i)

The equation of motion of the trolley is

T −fk =20a

fk =μk N

Here, μk =0.02,N =20×10 =200N

∴ T−0.02×200 =20a or T−2=20a …(ii)

Adding (i) and (ii), we get, a=3624ms−2 =1.5ms−2

Explanation:

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