Two carts, of inertias m1 and m2, collide head-on on a low-friction track. before the collision, which is elastic, cart 1 is moving to the right at 14 m/s and cart 2 is at rest. after the collision, cart 1 is moving to the left at 6 m/s . if the positive direction is from left to right, what is the speed of cart 2 after the collision?

Explanation:

As we know that momentum is always conserved in this type of collision

so we will have

so here we will have

also by the coefficient of restitution we know

so we have

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.