Two gliders of masses and move along a frictionless air track

PHYSICS · Single correct · A Level · Physics · Mechanics and materials · Mechanics and materials

Problem

Two gliders of masses

m_1

and

m_2

move along a frictionless air track. Glider 2 is initially at rest, and glider 1 has initial speed

v_{1i}

. The gliders collide elastically. Which expression gives the speed of glider 1 immediately after the collision? (a)

v_{1f}=\dfrac{2m_2}{m_1+m_2}\,v_{1i}

(b)

v_{1f}=\dfrac{m_1-m_2}{m_1+m_2}\,v_{1i}

(c)

v_{1f}=\dfrac{m_2-m_1}{m_1+m_2}\,v_{1i}

(d)

v_{1f}=\dfrac{2m_1}{m_1+m_2}\,v_{1i}