Question

A hammer weighing $3kg$, moving with a velocity of $10m/s$, strikes against the head of a spike and drives it into a block of wood. If the hammer comes to rest in $0.025s$, the impulse associated with the hammer will be

• A. $30Ns$
• B. $-30Ns$
• C. $15Ns$
• D. $-15Ns$

Answer 1

The correct option is B $-30Ns$

Let J be the impulse associated with the hammer

then, $\frac{\Delta J}{\Delta t}=ma$ and a =$\frac{\Delta V}{\Delta t}$

Hence, j = m$\Delta V$

j= 3(0 - 10) Ns = -30 Ns