The motion of a particle of mass $m$ is described by $y=u t+\frac{1}{2} g t^{2} .$ Find the force acting on the particle.
We know
$y=u t+\frac{1}{2} g t^{2}$
Now.
$v=\frac{ d y}{ d t}=u+g t$
acceleration, $a=\frac{ d v}{ d t}=g$
Then the force is given by $F=m a=m g$
Thus the given equation describes the motion of a particle under acceleration due to gravity and $y$ is the position coordinate in the direction of $g$
A $0.5\, kg$ ball moving with a speed of $12\,m/s$ strikes a hard wall at an angle of $30^o $ with the wall. It is reflected with the same speed at the same angle. If the ball is in contact with the wall for $0.25$ seconds, the average force acting on the wall is ........... $N$
A strange cat with a mass $m_c$ is sitting at rest on the left plank of a pair of identical planks. Each plank has mass $m_s$ and they rest on frictionless ice. Suddenly, the cat leaps to the right plank, traveling with a horizontal speed $v_{cg}$ measured with respect to the ground. The instant the cat reaches the right plank, it turns around and leaps back to the left plank. The horizontal component of the cat’s speed is again $v_{cg}$ measured with respect to the ground. The final speed of right plank in terms of the masses of the cat and planks and the cat’s leaping speed is (The cat remains on the left plank after its return).
On a stationary sail-boat, air is blown at the sails from a fan attached to the boat. The boat will
If impulse $I$ varies with time $t$ as $I\left( kg ms ^{-1}\right)=20 f^2-40 t$. The change in momentum is minimum at ........... $s$
The distance covered by a body of mass $5\,g$ having linear momentum $0.3\,kg\,m / s$ in $5\,s$ is $..........\,m$