A cricket ball of mass 150 g has an initial velocity $$\mathbf{u}=(3 \hat{\mathbf{i}}+4 \hat{\mathbf{j}}) \mathrm{ms}^{-1}$$ and a final velocity $$\mathbf{v}=-(3 \hat{\mathbf{i}}+4 \hat{\mathbf{j}}) \mathrm{ms}^{-1}$$, after being hit. The change in momentum (final momentum-initial momentum) is (in $$\mathrm{kgms}^{-1}$$ )

In the previous problem (3), the magnitude of the momentum transferred during the hit is

Conservation of momentum in a collision between particles can be understood from

A hockey player is moving northward and suddenly turns westward with the same speed to avoid an opponent. The force that acts on the player is

A body of mass 2 kg travels according to the law $$x(t)=p t+q t^2+r t^3$$ where, $$q=4 \mathrm{~ms}^{-2}, p=3 \mathrm{~ms}^{-1}$$ and $$r=5 \mathrm{~ms}^{-3}$$. The force acting on the body at $$t=2 \mathrm{~s}$$ is