The picture below shows a toy car in the process of rolling down a ramp. At point X, the kinetic energy is 50 Joules (J), and the potential energy is 30 J.

What is the total energy in the system once the car reaches the bottom of the ramp?
A
20 J, because the energy in the system cannot change form but can be created and destroyed

B
80 J, because the energy in the system can change form but cannot be created or destroyed

C
30 J, because the potential energy is the only energy at the bottom of the ramp

D
50 J, because the kinetic energy is the only energy at the bottom of the ramp

When the velocity of an object is doubled, by what factor is its momentum changed? by what factor is its kinetic energy changed? a) the momentum is zero. b) the momentum is not zero. c) difficult to say.

Aparticle of mass m is projected with an initial velocity v0 in a direction making an angle α with the horizontal level ground as shown in the figure. the motion of the particle occurs under a uniform gravitational field g pointing downward. (a) write down the lagrangian of the system by using the cartesian coordinates (x, y). (b) is there any cyclic coordinate(s). if so, interpret it (them) physically. (c) find the euler-lagrange equations. find at least one constant of motion. (d) solve the differential equation in part (c) and obtain x and y coordinates of the projectile as a function of time. (e) construct the hamiltonian of the system, h, and write down the hamilton’s equations (canonical equations) of motion.

Which type of wave can travel without a medium