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
A body with mass 5 kg is acted upon by a force $$\mathbf{F}=(-3 \hat{\mathbf{i}}+4 \hat{\mathbf{j}}) \mathrm{N}$$. If its initial velocity at $$t=0$$ is $$v=(6 \hat{\mathbf{i}}-12 \hat{\mathbf{j}}) \mathrm{ms}^{-1}$$, the time at which it will just have a velocity along the $$Y$$-axis is
A car of mass $$m$$ starts from rest and acquires a velocity along east, $$\mathbf{v}=v \hat{\mathbf{i}}(v>0)$$ in two seconds. Assuming the car moves with uniform acceleration, the force exerted on the car is
The motion of a particle of mass $$m$$ is given by $$x=0$$ for $$t<0$$ s, $$x(t)=A \sin 4 \pi t$$ for $$0
In figure the coefficient of friction between the floor and the body $$B$$ is 0.1. The coefficient of friction between the bodies $$B$$ and $$A$$ is 0.2. A force F is applied as shown on $$B$$. The mass of $$A$$ is $$\mathrm{m} / 2$$ and of $$B$$ is $$m$$. Which of the following statements are true?
