Working with gravitational force - calculation of the ratio of the radii of 2 planets

The weight of a object is the same on two different planets. The mass of planet A is only sixty percent that of planet B. Find ra/rb, which is the ratio of the radii of the planets.

Centripetal Force

In a skating stunt known as "crak-the-whip," a number of skaters hold hands and form a straight line. They try to skate so that the line rotates about the skater at one end, who acts as the pivot. The skater farthest out has a mass of 80.0 kg and is 6.10 m from the pivot. He is skating at a speed of 6.80 m/s. Determine the magni ...continues

Bnaked Curves

On a banked race track, the smallest circular path on which cars can move has a radius of 112 m, while the largest has a radius of 165 m. The height of the outer wall is 18 m. Find (a) the smallest (b) the largest speed at which cars can move on this track without relying on friction.

Apparent Weightlessness and artificial gravity

The moon orbits the earth at a distance of 3.85 x 10^8 m. Assume that this distance is between the centers of the earth and the moon and that the mass of the earth is 5.98 x 10^24 kg. Find the period for the moons motion around the earth. Express the answer in days and compare it to the length of a month.

Vertical Circular motion

A roller coaster at an amusement park has a dip that bottoms out in a vertical circle of radius r. A passenger feels the seat of the car pushing upward on her with a force equal to twice her weight as she goes through the dip. If r + 20.0 m, how fast is the roller coaster traveling at the bottom of the dip?

torque and static equilibrium

A uniform metal rod, with a mass of 3.1 kg and a length of 1.2m, is attached to a wall by a hinge at its base. A horizontal wire bolted to the wall 0.51 m above the base of the rod holds the rod at an angle of 25 degrees above the horizontal. The wire is attached to the top of the rod. (a) Find the tension in the wire. (b) ...continues

word problem

In his novel "From the earth to the moon", Jules Verne imagined that astronauts inside a space ship would walk on the floor of the cabin when the force exerted on the ship by the earth was greater than the force exerted by the moon. When the force exerted by the moon was greater he thought the astronauts would walk on the ceili ...continues

The Gravitational Force

In tests on Earth a lunar surface exploration vehicle (mass = 5.90 x 10^3 kg) achieves a foward acceleration of 0.220 m/s^2. To achieve this same acceleration on the moon, the vehicle's engines must produce a drive force of 1.43 x 10^3 N. What is the magnitude of the frictional force that acts on the vehicle on the moon?

Newtons Second Law of Motion A boat has a mass of 6800 kg. Its engines generate a drive force of 4100 N, due west,while the wind exerts a force of 800 N, due east, and the water exerts a resistive force of 1200 N due east. What is the magnitude and direction of the boats acceleration?

A boat has a mass of 6800 kg. Its engines generate a drive force of 4100 N, due west,while the wind exerts a force of 800 N, due east, and the water exerts a resistive force of 1200 N due east. What is the magnitude and direction of the boats acceleration?

Nonequilibrium Applicastions of Newtons Laws of Motion A crate is resting on a ramp that is inclined at an angle 0(thada) the horizontal.As 0(thada) is increased, the crate remains in place until 0(thada)reaches a value of 38.0 degrees. Then the crate begins to slide down the slope. (a) Determine the coefficient of static friction between the crate and the ramp surface. (b) The coefficient of kinetic friction between the crate and the ramp surface is 0.600. Find the accelerration of the moving crate.

A crate is resting on a ramp that is inclined at an angle 0(thada) the horizontal.As 0(thada) is increased, the crate remains in place until 0(thada)reaches a value of 38.0 degrees. Then the crate begins to slide down the slope. (a) Determine the coefficient of static friction between the crate and the ramp surface. (b) The coef ...continues