Samples of different materials, A and B, have the same mass, but the sample of A is higher in density. Which statement could explain why this is so?
A. The sample of material A has greater volume than the sample of
material B.
B. The particles that make up material B have more mass than the
particles that make up material A.
C. The particles that make up material B are more closely packed
together than the particles that make up material A.
D. The particles that make up material A have more mass than the
particles that make up material B.

The man of mass m1 and the woman of mass m2 are standing on opposite ends of the platform of mass m0 which moves with negligible friction and is initially at rest with s = 0. the man and woman begin to approach each other. derive an expression for the displacement s of the platform when the two meet in terms of the displacement x1 of the man relative to the platform.

What is the kinetic energy of a baseball moving at a speed of 40 m/s if the baseball has mass of 0.15 kg?

Anonzero net force acts on a particle and does work. which one of the following statements is true? the kinetic energy of the particle changes, but the speed of the particle does not change. the kinetic energy of the particle does not change, but the speed of the particle does change. the kinetic energy of the particle changes, but the velocity of the particle does not change. the kinetic energy and the speed of the particle change, but the velocity of the particle does not change. the kinetic energy, speed, and velocity of the particle change.