Mechanics | Relativity Answers

A hose ejects water at 80cl/s through a hole 2mm in diameter. The water impinged on a wall and drops off without rebounding. What is the force on the wall?

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

A worker on a roof, 20.8 m above the ground, wants to drop a brick onto the back of a moving truck. The
truck is moving at a constant velocity of 5.0 m/s alongside the building. The back of the truck is 1.2 m
above the ground. How far from the point of impact must the truck be, the instant the brick is dropped, so
that the brick will land on the back of the truck?

Pistons are free to move in two cylinders which are connected by a hydraulic fluid. The area of the smaller piston is 1.2 cm2. A force of 150 N on this piston will move a weight of 2700 N on the larger piston. (Assume that friction is negligible.)
A) What is the area of the large piston?
B) What is the pressure in the fluid? (Give answer in Pascals)

A 3.0 kg object with a volume of 750 cm3 is hanging from a scale. The object is then lowered so it is submerged completely in an unknown fluid. The scale now reads 20.0 N.
A) What is the magnitude of the buoyant force acting on the object?
B) What is the density of the fluid?

A screw has a pitch equal to 0.5mm .What should be the number of division on its head so as to read correct up to 0.001 mm with its help

A steel ball A of mass 20.0 kg moving with a speed of 2.0 ms−1 collides with another ball B of mass 10.0 kg which is initially at rest. After the collision A moves off with a speed of 1.0 ms−1 at an angle of 30º with its original direction of motion. Determine the final velocity of B.

A projectile is launched straight up at 60.0 m/s from a height of 80.0 m, at the edge of a sheer cliff. The projectile falls, just missing the cliff and hits the ground below. a. What is the maximum height of the projectile above the point of firing? b. How long does it take to hit the ground below the cliff? c. What is the projectile’s velocity upon impact with the ground?

Calculate the time in seconds it will take an average man with life expectancy with seventy years taking into consideration the leap year

A marble and a cube are placed at the top of a ramp. Starting from rest at the same height, the marble rolls without slipping and the cube slides (no kinetic friction) down the ramp. Determine the ratio of the center-of-mass speed of the cube to the center-of-mass speed of the marble at the bottom of the ramp.