Two balls undergo a perfectly elastic head-on collision, with one ball initially at rest. if the incoming ball has a speed of 200 m/s . part a part complete what is the final speed of the incoming ball if it is much more massive than the stationary ball? express your answer using two significant figures. v1 = 200 m/s submitprevious answers correct part b part complete what is the final direction of the incoming ball with respect to the initial direction if it is much more massive than the stationary ball? forward submitprevious answers correct part c part complete what is the final speed of the stationary ball if the incoming ball is much more massive than the stationary ball? .

what is the final speed of the incoming ball if it is much more massive than the stationary ball? express your answer using two significant figures. v1 = 200 m / s submitprevious answers correct
 Perfectly elastic collisions means that both mechanical energy and
momentum are conserved.
 Therefore, for this case, we have the equation to find the final velocity of the incoming ball is given by
 v1f = ((m1-m2) / (m1 + m2)) v1i
 where,
 v1i: initial speed of ball 1.
 v1f: final speed of ball 1.
 m1: mass of the ball 1
 m2: mass of the ball 2
 Since the mass of the ball 1 is much larger than the mass of the ball 2 m1 >> m2, then rewriting the equation:
 v1f = ((m1) / (m1) v1i
 v1f = v1i
 v1f = 200 m / s
 answer
 200 m / s
 part b part complete what is the final direction of the incoming ball with respect to the initial direction if it is much more massive than the stationary ball? forward submitprevious answers correct

 Using the equation of part a, we can include in it the directions:
 v1fx = ((m1-m2) / (m1 + m2)) v1ix
 v1i: initial velocity of ball 1 in the direction of the x-axis
 v1f: final speed of ball 1 in the direction of the x-axis
 like m1 >> m2 then
 v1fx = v1ix
 v1fx = 200 m / s (positive x direction)
 So it is concluded that the ball 1 continues forward.
 
 forward

 part c part complete what is the final speed of the stationary ball if the incoming ball is much more massive than the stationary ball ?.
 The shock is perfectly elastic. For this case, we have that the equation to find the final velocity of the stationary ball is given by
 v2f = ((2m1) / (m1 + m2)) v1i
 where,
 v1i: initial speed of ball 1.
 v2f: final speed of ball 2.
 m1: mass of the ball 1
 m2: mass of the ball 2
 Then, as we know that m1 >> m2 then
 v2f = ((2m1) / (m1) v1i
 v2f = 2 * v1i
 v2f = 2 * (200 m / s)
 v2f = 400 m / s
 answer
 400m / s