Why is the science of astronomy considered one of the oldest sciences?

What is the coefficient of kinetic friction μk between the block and the tabletop?

The drag force, fd, imposed by the surrounding air on a vehicle moving with velocity v is given by fd = cdaρv 2/2 where cd is a constant called the drag coefficient, a is the projected frontal area of the vehicle, and ρ is the air density. an automobile is moving at v = 80 kilometers per hour with cd = 0.28, a = 2.3 m2, and ρ = 1.2 kg/m3.

Abus travels 280km south along a straight path with an average velocity of 88km/h to the south. the bus stops for 24 min, then it travels 210 km south with an average velocity of 75 km/h to the south. how long does the total trip last?