A roller coaster car travels up and down the hills of its track. Neglecting
friction, the sum of its kinetic and potential energy
A. equals the sum of the thermal energy generated by
friction during the ride.
B. is a function of the length of the track.
C. cannot be calculated after the first hill and valley.
D. must always remain constant.

If an athlete runs once around a track, back to the starting line, her average velocity is zero. true or false?

Suppose that a mass of 2 kg is attached a spring whose spring constant is 50. the system is damped such that b = 12 . the mass is set in motion with an initial velocity of -8 m/s at a position 0 meters from equilibrium. set up and solve a differential equation that models this motion. write your solution in the form a cos ( ω t − α ) where α is a positive number. use your solution to fill in the information below: what is the amplitude of the motion? what is the value of ω ? what is the phase shift?

Would it be correct to say the doppler effect is the apparent change in the speed of a wave due to the motion of the source? be sure to fully explain your position using at least 3 complete content related sentences.