Question

A $5gm$ lump of clay, moving with a velocity of $10cm/s$ towards east, collides head-on with another $2gm$ lump of clay moving with $15cm/s$ towards west. After collision, the two lumps stick together. The velocity of the compound lump will be-

• A. 5 cm/s towards east
• B. 5 cm/s towards west
• C. 2.88 cm/s towards east
• D. 2.5 cm/s towards west

Answer 1

The correct option is C 2.88 cm/s towards east

Given that,

$m_1=5g$

$m_2=2g$

$v_1=10cm/s$

$v_2=15m/s$

Now, according to the law of conservation

$m_1{v}_1+m_2{v}_2=(m_1+m_2)v$

$5\times 10-2\times 15=7v$

$v=\frac{20}{7}$

$v=2.88cm/s$

Hence, the velocity is $2.88cm/s$ in east