Mechanics | Relativity Answers

A 30,000 kg railroad car initially traveling to the right at 15 m/s collides inelastically with a 20,000 kg railroad car initially traveling to the left at 5 m/s. The cars stick together. What is their final speed?

A force of 44.0 N accelerates a 5.0-kg block at 6.3 m/s2 along a horizontal surface.

How large is the frictional force?
and What is the coefficient of friction?

Water at a pressure of 3.6 atm at street level flows into an office building at a speed of 0.4 m/s through a pipe 6 cm in diameter.The pipes taper down to 2.8 cm in diameter by the top floor,28 m above.Calculate the water pressure in such a pipe on the top floor.(g=9.8 m/s square)

A lead block is suspended from the undesired of a 0.4 kg block of wood of density of 720 kg/per meter cube. If the upper surface of the wood is just level with water. What is the mass of the lead block.Density of lead is 11340 kg per meter cube.

A U-tube contain liquid of unknown density.An oil of density 778kg/m3 is poured into one arm of the tube until the oil column is 10 cm high.The oil air interface is then 7 cm above the liquid level in the other arm of U tube.Find the density of the liquid.

A 250 N object with three-fourths of its volume beneath the surface of the water.what is the bouyant force on the object?

A university physics professor buys 100 of string and determines its total mass to be 0.150 . This string is used to set up a standing wave laboratory demonstration between two posts 3.0 apart.If the desired second harmonic frequency is 35 , what should be the required string tension?

A command post (O) monitors th movement of two ships in the gulf. At 1200 hrs a battleship (b) has bosition (-2i+10j)km relative to (O) and has constant velocity of (3i+2j)km/h , where i and j are unit vectors directed due east and due north respectively .

a)the captain of one ship has e been taken ill , show that the two ships will collide . the command post contacts the battleship and orders it to reduce its speed to move with velocity (2i+2j)km/h

b)find an expression for the vector [BF] at time t hours after noon

c)find the distance between B and F at 1400hrs

d)find the time at which F will be due north of B

As a prank, someone has balanced a pumpkin near the highest point of a grain silo. The silo is topped with a hemispherical cap that is frictionless when wet. The line from the center of curvature of the cap to the pumpkin makes an angle θi = 3.2° with the vertical. While you happen to be standing nearby in the middle of a rainy night, a breath of wind makes the pumpkin start sliding downward from rest. It loses contact with the cap when the line from the center of the hemisphere to the pumpkin makes a certain angle with the vertical. What is this angle, to the nearest 0.1°?

length of a spring is 50cm. calculate the final extension after 100 N load exerts on it.(k=50)