I need help with this problem: It's motion of a pointrelated: Ball A is released from rest at a height of 40 ft. at the sametime that a second ball B is thrown upward 5 ft. from the ground.If the balls pass one another at a height of 20 ft. determine thespeed at which ball B was thrown upward. I need help with this problem: It's motion of a pointrelated: Ball A is released from rest at a height of 40 ft. at the sametime that a second ball B is thrown upward 5 ft. from the ground.If the balls pass one another at a height of 20 ft. determine thespeed at which ball B was thrown upward.
Explanation / Answer
Assume g = 32 ft/s^2 . Ball A ha.i = 40 ft Equation of motion for A y = ha.i - 1/2 g t^2 Set y = 20 ft 20 ft = 40 ft - 1/2 g t^2 t^2 = (40ft-20ft) *2/g t^2 = (40ft-20ft) *2/(32ft/s^2) t = 1.118 seconds . Ball B hb.i = 5ft Equation of motion for B y = hb.i + v t - 1/2 gt^2 v = (y - hb.i + 1/2 g t^2)/t Sub in y = 20ft and t = 1.118 s, hb.i and g v = (20 ft - 5 ft + 1/2 (32ft/s^2) * (1.118s)^2) /(1.118s) v = 31.3 ft s