In phase would mean both waves are at a positive peak, out of phase would mean one is at a positive whilst the other is at a negative. Out of phase would mean the waves cancel each other out
Answer:
a toy car speed is about 2.5 to 3.5 mph
Answer:
-1500 m/s2
Explanation:
So the ball velocity changes from 10m/s into the wall to -8m/s in a totally opposite direction within a time span of 0.012s. Then we can calculate the average acceleration of the ball as the change in velocity over a unit of time.

Let's call

the mass of the glider and

the total mass of the seven washers hanging from the string.
The net force on the system is given by the weight of the hanging washers:

For Newton's second law, this net force is equal to the product between the total mass of the system (which is

) and the acceleration a:

So, if we equalize the two equations, we get

and from this we can find the acceleration: