Provide an example from daily life where motion is controlled or initiated by an external force.

$A$ metal block is resting on a rough wooden surface. $A$ horizontal force applied to the block is increased uniformly with time, given by $F = kt$. Which of the following curves correctly represents the velocity of the block as a function of time?

$A$ sphere of mass $m$ and radius $R$ is kept on a rough horizontal surface and pulled with a horizontal force $F = \alpha t$,where $\alpha$ is a constant and $t$ is time. The coefficient of static friction is $\mu_s$ and the coefficient of kinetic friction is $\mu_k$. Which of the following graphs correctly shows the variation of the acceleration of the sphere with time?

$A$ balloon of mass $M$ is descending at a constant acceleration $\alpha$. When a mass $m$ is released from the balloon,it starts rising with the same acceleration $\alpha$. Assuming that its volume does not change,what is the value of $m$?

$A$ cold soft drink is kept on a balance. When the cap is opened,the weight reading on the balance:

$A$ block of mass $m$ is placed on a smooth horizontal surface. $A$ force making an angle $\theta$ with the horizontal starts acting on the block. The magnitude of the force is constant but its direction with the horizontal changes as $\theta = a + bs$,where $a$ and $b$ are constants and $s$ is the distance covered by the block. If $|F| = 2mb$,find the velocity of the block as a function of the angle $\theta$.