CBSE-XI-Physics

05: Newton's Laws of Motion

with Solutions - page 6
Qstn# iv-26 Prvs-QstnNext-Qstn
  • #26
    A constant force F = m2g/2 is applied on the block of mass m1 as shown in figure (5-E10). The string and the pulley are light and the surface of the table is smooth. Find the acceleration of m1.
    Figure
    Ans : The free-body diagrams for both the blocks are shown below:

    From the free-body diagram of block of mass m1,
    m1a = T - F ...(i)
    From the free-body diagram of block of mass m2,
    m2a = m2g - T ...(ii)
    Adding both the equations, we get:
    `` a\left({m}_{1}+{m}_{2}\right)={m}_{2}g-\frac{{m}_{2}g}{2}\left[\,\mathrm{\,because \,}F=\frac{{m}_{2}g}{2}\right]``
    `` \Rightarrow a=\frac{{m}_{2}g}{2\left({m}_{1}+{m}_{2}\right)}``
    So, the acceleration of mass m1,
    `` a=\frac{{m}_{2}g}{2\left({m}_{1}+{m}_{2}\right)},\,\mathrm{\,towards \,}\text{ the }\,\mathrm{\,right \,}.``
    Page No 81: