Could somebody please explain each step very clearly as I am having more trouble
ID: 1779064 • Letter: C
Question
Could somebody please explain each step very clearly as I am having more trouble more with parts B-D please and thank you!
Suppose that a 107.5 kg football player running at 6.5 m/s catches a 0.45 kg ball moving at a speed with his feet off the ground, while both of them are moving horizontally.
A. Calculate the final speed of the player, in meters per second, if the ball and player are initially moving in the same direction.
B. Calculate the change in kinetic energy of the system, in joules, after the player catches the ball.
C. Calculate the final speed of the player, in meters per second, if the ball and player are initially moving in opposite directions.
D. Calculate the change in kinetic energy of the system, in joules, in this case.
Explanation / Answer
A)
M = mass of the player = 107.5 kg
Vi = initial velocity of the player = 6.5 m/s
m = mass of ball = 0.45 kg
vi = initial velocity of ball = v
V = final speed of the combination
using conservation of momentum
MVi + m vi = (M + m) V
(107.5) (6.5) + (0.45) (v) = (107.5 + 0.45) V
V = (698.75 + (0.45) (v) )/(107.95)
B)
change in kE = (0.5) ((M + m) V2 - M Vi2 - m vi2)
c)
M = mass of the player = 107.5 kg
Vi = initial velocity of the player = 6.5 m/s
m = mass of ball = 0.45 kg
vi = initial velocity of ball = v
V = final speed of the combination
using conservation of momentum
MVi - m vi = (M + m) V
(107.5) (6.5) - (0.45) (v) = (107.5 + 0.45) V
V = (698.75 - (0.45) (v) )/(107.95)