Mechanics | Relativity

A flagpole weighs 53kg with a flag. The flagpole is 8.4 m long. The flagpole is attached to the wall partly at point A and partly with a horizontal line extending from the top end of the flagpole. The center of gravity of the flagpole and flag is in the bar 5.0 m from the point A. The angle between the bar and the wall is 45 degrees as the figure shows.
Determine the power of the cable.

Mechanics | Relativity

Ball 1 is moving toward you at 11 m/s , and you decide to throw ball 2 at it to make it reverse its velocity. The balls collide head-on, and the coefficient of restitution for the collision is 0.90. Ball 1 has an inertia of 0.500 kg and ball 2 has an inertia of 0.650 kg . Call the direction of motion in which we throw ball 2 the +x direction.
1.How fast must ball 2 be traveling in order to reverse the velocity of ball 1?
2.What is the initial relative speed of the two balls?
3.How do the balls initially move?
4.What is their reduced inertia?
5.What percentage of the original kinetic energy is convertible?
6.What is the x-component of the final velocity of the ball 1 immediately after the collision
7.What is the x-component of the final velocity of the ball 2 immediately after the collision?

Mechanics | Relativity

A machine with a mass of 4kg fires a 45g bullet at a speed of 100m/s...
What is the recoil speed of the machine gun

Mechanics | Relativity

A stone is released freely from a 200 m tall building. Calculate the final veocity of the stone just before touching the ground. Ignore the friction of air. (use g = 9.81 ms-1)

Mechanics | Relativity

A ball is in free fall. Upward is taken to be the positive direction. The displacement of the ball during a short time interval is: ( )

Mechanics | Relativity

A dog sits 1.40 m from the center of a merry- go-round with an angular speed of 1.94 rad/s. If the magnitude of the force that maintains
the dog’s circular motion is 36.2 N, what is the dog’s mass?
Answer in units of kg.

Mechanics | Relativity

Find the hydrostatic pressure exerted on an object that is 4.45 m below the surface of gasoline and its absolute pressure. The density of gasoline is 680 kg/m3.

Mechanics | Relativity

Water flows through a pipe with an area of 13 in2 with a speed of 12 ft/s. It then enters a smaller pipe with an area of 3.1 in2. What is the speed of the water as it flows through the smaller pipe?

Mechanics | Relativity

A piece of metal displaces 3.56×10-5 m3 of water. Find the buoyant force.

Mechanics | Relativity

In a hydraulic press, the area of the small piston is 25.0 cm2 and the area of the large piston is 325 cm2. If a force of 75.0 N is exerted on the small piston, find the weight of the object that can be lifted by the large piston.