A ball moving with a velocity v strikes a wall moving toward the ball with a velocity u. An elastic impact lasts for t sec. Then the mean elastic force acting on the ball is ;

A heavy ball moving with speed $v$ collides with a tiny ball. The collision is elastic, then immediately after the impact, the second ball will move with a speed approximately equal to-

A particle of mass $m_0$, travelling at speed $v_0$, strikes a stationary particle of mass $2m_0$. As a result, the particle of mass $m_0$ is deflected through $45^o$ and has a final speed of $\dfrac {v_0}{\sqrt 2}$. Then the speed of the particle of mass $2m_0$ after this collision is

10 m উপর হতে 10 kg ভরের একটি মুক্তভাবে পড়ন্ত বস্তুর মাটি থেকে 5 m উচুতে মোট শক্তি কত হবে? 

A sphere of mass m, moving with a speed v, strikes a wall elastically at an angle of incidence $\theta$. If the speed of the sphere before and after the collision is the same and the angle of incidence and velocity normally towards the wall the angle of rebound is equal to the angle of incidence and velocity normally towards the wall is taken as negative then, the change in the momentum parallel to the wall is :

m ভরের একটি বস্তু যা v বেগে গতিশীল থাকা অবস্থায় k