Hockey puck A with mass 156 grams gliding at 3.55 m/s on ice (frictionless) overtakes and impacts another, slower hokey puck B from behind sliding in the same direction at 1.45 m/s. after the impact, puck A slows to 2.15 m/s in the same direction while puck B (hit from behind) begins gliding at 2.55 m/s in the same direction. (elastic collision occurred)

Is the mass of hockey puck B identical to A?
If not, what is it?
What is the kinetic energy of puck A before the collision? After?

power out to power in less than 100%

0.11 m/s and 0.28 m/s should be correct

air exerts forces on falling objects near earth’s surface.

explanation:

the term 'free falls' refer to object that are falling towards the earth, in a situation in which gravity is the only force acting on the object.

for an object in free fall, the acceleration is constant (g, the gravitational acceleration), and so the velocity of the object constantly increases.

for objects near earth's surface, there is always another force acting on the object: the resistance due to the air. this force is opposed to the direction of fall of the object, and it is proportional to the velocity of the object, so as the object falls down, this force increases up to a point when it balances the force of gravity, and the object continues its motion at constant velocity (called terminal velocity). since in this case gravity is not the only force acting on the object, we are not in a situation of free fall.

pythagoras' theorem

square root (-5^2+9^2)

square root (25+81)

square root (106)

angle is tan^-1(9/5)

neg x, pos y