Which has the highest inertia among solids made of aluminium,steel,and wood of the same shape and same volume?

State Newton's first law of motion.

$A$ player catching a moving ball moves his hand backwards. Why?

$A$ large truck and a car,both moving with a velocity of magnitude $v$,have a head-on collision and both of them come to a halt after that. If the collision lasts for $1$ second:
$(i)$ Which vehicle experiences the greater force and why?
$(ii)$ Which vehicle experiences the greater change in momentum and why?
$(iii)$ Which vehicle experiences the greater acceleration and why?

$(a)$ State Newton's second law of motion. Use this law to find a method to measure force acting on an object.
$(b)$ From a rifle of mass $4 \ kg$,a bullet of mass $50 \ g$ is fired horizontally with an initial velocity of $40 \ m \ s^{-1}$. Calculate the initial recoil velocity of the rifle.

$A$ certain force exerted for $1.2 \, s$ raises the speed of an object from $1.8 \, m s^{-1}$ to $4.2 \, m s^{-1}$. Later, the same force is applied for $2 \, s$. How much does the speed change in $2 \, s$?