sample of blood is placed in a centrifuge of radius 11.0 cm. The mass of a red blood cell is 3.0 ✕ 10−16 kg, and the magnitude of the force acting on it as it settles out of the plasma is 4.0 ✕ 10−11 N. At how many revolutions per second should the centrifuge be operated?

A moon travels around an unknown planet. If the period of the orbit is 1 day, and the radius of the orbit is 1.37 x 10^7 m, what is its speed in m/s?

Astronomers discover an exoplanet, a planet orbiting a star other than the Sun, that has an orbital period of 3.50 Earth years in a circular orbit around its star, which has a measured mass of 3.80 × 10³0 kg. Determine the radius r of the exoplanet's orbit. r = m

I whirl John (mass 0.27 kg) over my head in a circle. There is a spring scale between my hand and the string, so I can measure the force of tension in the string, which I find to be 2.12 N. I measure the length of the string (the radius of the circle) and find it to be 1.34 m. Assuming that John's speed is not changing, how fast is he going?

HINT M. kg (a) Find the magnitude of the gravitational force (in N) between a planet with mass 6.50 x 1024 and its moon, with mass 2.55 x 10 kg, if the average distance between their centers is d= 2.90 x 108 m. %3D N (b) What is the moon's acceleration (in m/s2) toward the planet? (Enter the magnitude.) m/s? (c) What is the planet's acceleration (in m/s²) toward the moon? (Enter the magnitude.) m/s2

A puck of mass m = 1.30 kg slides in a circle of radius r = 22.0 cm on a frictionless table while attached to a hanging cylinder of mass M= 2.30 kg by a cord through a hole in the table. What speed keeps the cylinder at rest? M Number i 2.227 Units m/s

=J (e) (b) Fe= () 6. A pendulum that consists of a ball (m = 1.50 kg) attached to a light cord rotates in a circular path of radius r = 0.800 m at constant speed v, as shown in Figure. Here the angle 0 = 65°, and we ignore air friction and assume the mass of the light cord is negligible. (a) Calculate the tension T in the cord. = L. (b) Calculate the centripetal force acting on the ball. = 'd (c) Calculate the velocity v of this uniform circular motion. Answers:

A satellite of Mars, called Phobos, has an orbital radius of 9.4 ✕ 106 m and a period of 2.8 ✕ 104 s. Assuming the orbit is circular, determine the mass of Mars. (ans kg)

a) An object weights 4000 N on planet Alpha. Planet Alpha has 8 times the mass of planet Beta and 4 times the radius of planet Beta. What will the object weight on planet Beta?   b) A 60 kg person is sitting on a bathroom scale while riding on a Ferris Wheel. The Ferris Wheel has a radius of 9 m and the person's speed is 3 m/s. Find the scale reading when the person is at the bottom of the motion.

A satellite is launched to orbit the Earth at an altitude of 1.80 x 107 m for use in the Global Positioning System (GPS). Take the mass of the Earth to be 5.97 x 1024 kg and its radius 6.38 x 106 m. (a) What is the orbital period of this GPS satellite? h (b) With what speed does it orbit the Earth? m/s