Which of the following is the most accurate description of the relationship between velocity and acceleration? Velocity and acceleration are the same thing.

Velocity is a type of acceleration.

Acceleration is a change in velocity.

Acceleration is positive and velocity is negative.

Can somebody explain to me how newton's 3rd law relates to momentum? ~ap physics 1

Ablock of mass m = 2.5 kg is attached to a spring with spring constant k = 710 n/m. it is initially at rest on an inclined plane that is at an angle of θ = 23° with respect to the horizontal, and the coefficient of kinetic friction between the block and the plane is μk = 0.19. in the initial position, where the spring is compressed by a distance of d = 0.16 m, the mass is at its lowest position and the spring is compressed the maximum amount. take the initial gravitational energy of the block as zero. a) what is the block's initial mechanical energy? b) if the spring pushes the block up the incline, what distance, l, in meters will the block travel before coming to rest? the spring remains attached to both the block and the fixed wall throughout its motion.

If steel is more dense that lake water, why can a boat float