Question

A glider of mass 5.0 kg hits the end of a horizontal rail and bounces off with the same speed, in the opposite direction. The collision is elastic and takes place in a time interval of 0.2s, with an average force of 100N. What was the speed, in m/s, of the glider?A glider of mass 5.0 kg hits the end of a horizontal rail and bounces off with the same speed, in the opposite direction. The collision is elastic and takes place in a time interval of 0.2s, with an average force of 100N. What was the speed, in m/s, of the glider?

Answer 1

To develop this problem it is necessary to apply the equations concerning the conservation of the moment.

By definition the moment can be expressed in two ways,

The first as a function of force and because of time, that is

$\Delta P = F \Delta t$

And also based on mass and speed

$\Delta P = m_2v_2-m_1v_1$

Speed 1 is moving in the opposite direction to our reference system and it remains constant, as is the mass therefore

$\Delta P = mv-(-mv)$

$\Delta P = 2mv$

Equation both expression we have that,

$2mv = F\Delta t$

$v = \frac{F\Delta t}{2m}$

$v = \frac{100*0.2}{2(5)}$

$v = 2m/s$

Therefore the speed of the glider is 2m/s