equilibrium

A uniform plank with a length L of 6.10 m and a weight of 445 N, rests on the ground and against a frictionless roller at the top of the wall of height h = 3.05 m. The plank remains in equilibrium for any value of theta greater than or equal to 70 degress but slips if theta is less than 70 degrees. Find the coefficient of st ...continues

Calculating the separation between two uniform spheres during gravitation.

From an inertial frame in space, we watch two identical uniform spheres fall toward one another owing to their mutual gravitational attraction. Approximate their initial speed as zero and take the initial gravitational potential energy of two-sphere system as Ui. When the separation between the two spheres is half the initial ...continues

Calculating the separation between two masses to attain a specified gravitational attraction.

What must the separtion be between a 5.2 kg particle and a 2.4 kg particle for their gravitational attraction to have a magnitude of 2.3 X 10(-12) N?

Gravitation

How far from Earth must a space probe be along a line toward the Sun so that the Sun's gravitational pull on the probe balances the Earth's pull?

Calculating the altitude above Earth's surface to attain a specified acceleration due to gravity.

At what altitude above the Earth's surface would the gravitational acceleration be 4.9 m/s^?

Gravitation

Certain neutron stars (extremely dense stars) are believed to be rotating at about 1 rev/s. If such a star has a radius of 20 km, what must be its minimum mass so that material on its surface remains in place during the rapid rotation?

Gravitation

A rocket is accelerated to speed v = 2 sq. root gRe near Earth's surface (where Earth's radius is Re), and it then coasts upward. a) Show that it will escape from Earth. b) Show that very far from Earth its speed will be v = sq. root 2gRe.

Calculating the linear speed of a satellite in a circular orbit and the period of revolution.

What linear speed must an Earth's satellite have to be in a circular orbit at an altitude of 160 km? What is the period of revolution?

Finding the total mechanical energy of an inelastic satellite collision.

Consider two satellites, A and B, both of mass m, moving in the same circular orbit of radius r around the Earth, of mass Me, but in opposite senses of rotation and therefore on a collision course. a) In terms of G, Me, m, and r, find the total mechanical energy Ea and Eb of the two satellites plus Earth's system before col ...continues

Calculating the time it takes to heat a specified amount of water.

A 5000W heater is used to heat water. How long will it take to heat 20 kg of water from 20 degrees C to 100 degrees C assuming perfect efficiency?