Tom is 20 years old when he boards a spaceship that flies at 0.800c toward planet x which is 12 lightyears away. left behind on earth is his twin brother tim. upon reaching planet x, tom immediately turns back and returns to earth at a slower speed of 0.600c. what is the biological age of tim upon tom's arrival on earth?
a. 55 yrs old
b. 45 yrs old
c. 40 yrs old
d. 50 yrs old

In which of the following cases is work being done on an object? question 2 options: pulling a trailer up a hill carrying a box down a corridor suspending a heavy weight with a strong chain pushing against a locked door

Two steel balls, each of mass m, are welded to a light rod of length l and negligible mass and are initially at rest on a smooth horizontal surface. a horizontal force of magnitude f is suddenly applied to the rod as shown. determine (a) the instantaneous acceleration a of the mass center g and (b) the corresponding rate at which the angular velocity of the assembly about g is changing with time.

Name two kinds of practical electric pumps.