The car bounces off and moves in the opposite direction
Yes potential increases while kinetic decreases
The vector, the x-component and the y-component form a rectangle triangle where the vector is the hypothenuse and the x and y components are the two sides.
Calling

the angle between the vector and the horizontal direction (x), the two sides are related to

by

where vy and vx are the two components on the y- and x-axis. Using vx=10 and vy=3 we find

And so the angle is
Answer:
36 N
Explanation:
Velocity of a standing wave in a stretched string is:
v = √(T/ρ),
where T is the tension and ρ is the mass per unit length.
300 m/s = √(T / 4×10⁻⁴ kg/m)
T = 36 N