1.) At an amusement park, a bumper car and rider have a mass of 175 kg and are moving at a speed of 8.0 m/s. The first bumper car collides with a stationary second bumper car and rider that have a mass of 125 kg. After the collision, the first bumper car continues moving with a speed of 3.85 m/s. Calculate the velocity of the second bumper car after the collision. What is the direction that the second car is moving?

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.

Consider a system with two masses that are moving away from each other. why will the kinetic energy differ if the frame of reference is a stationary observer or one of the masses?

4. if you were an astronaut on the moon, what would you experience? what would you see from your perspective?