Mechanics | Relativity Answers

A particle, P, of mass 4kg was released with an initial velocity of 4m/s from a height of 80m above the horizontal ground. At the same time, another particle Q of mass 2kg was thrown vertically upwards with a velocity of 30m/s from the same horizontal ground directly below P. If the particles collide at a distance of 5m from the ground, calculate, correct to one decimal place, the 

i) time when P and Q collided

ii) velocities of the particles at the point of collision. 

iii) common velocity after the collision, if they moved together after collision.

An isolated thermodynamic system, composed of an ideal gas, completes a cycle reversible consisting of an isothermal expansion (1-2), an isochoric cooling (2-3) and an adiabatic transformation (3-1). Knowing that V2= 3V1, and that = 7/5 = 1.4, Calculate:

a)      The thermal efficiency of the cycle.

b)     Is the gas monoatomic or diatomic cycle?

c)      The change in entropy of the individual transformations of the system and in the whole cycle.

d)     The change in entropy of the universe.

A ball rolls off the edge of a horizontal table top 2.3 ft high. It strike the floor at a point 5.11 ft horizontally away from the edge of the table  a) For how long was the ball in air  b) what was the speed at the instant it left the table.

The resistance of a Thermistor at -100c is 200kilo ohms

What is the ratio of the resistance at 400c to this resistance if the material constant is 4000kelvin

assume the spring constant in this lab is 10 N/m. if a mass of 1 lb is attached and the mass pulls for 5 inches. when the mass is released what will be its max minim speed going up in m/s,

and what will be it’s maximum acceleration in m/s?

A student sends vertically to the floor, from the height H1 = 1,35m, a ball with the mass m = 400 g. The initial speed of the ball is V0 = 3M / s.

. Immediately after collision with the floor, the ball speed is facing vertically and

It is a fraction K of the ball's speed immediately before hitting the floor. The ball goes back up up to the maximum height H2 = 1.25M

. The air friction forces are negligible. Potential gravitational energy is considered null at the floor level, and the dimensions of the ball are neglected. Determine:

a. Total mechanical energy of the ball at the time of launch;

b. the ball pulse value immediately after collision with the floor;

A load of 37 N attached to a spring hanging vertically stretches the spring 3.4 cm. The spring is now placed horizontally on a table and stretched 15 cm. What force is required to stretch it by this amount? Answer in units of N.

In free fall motion topic, what we will take the value of (g), either we take positive for downward motion and take negative for upward motion? kindly help me in this

thanks

A screw jack has a two-start thread of pitch 5mm. An effort of 40N is applied tangentially to the tommy bar, at a radius of 350 mm, to lift a load of 2200 N.

1. Calculate the velocity ratio and the mechanical advantage of the jack.
2. Calculate the work done in overcoming friction when the load is raised a distance of 75 mm.
3. Evaluate the efficiency of the screw jack and discuss what effect it has on the likelihood of overhauling and the law of the machine.

. A carpenter and his assistant are to carry a uniform wooden beam, which is 6 m long and weighs 100 kg, on their shoulders. Both men are of the same height so that the beam is carried horizontally. However, the carpenter is the stronger of the two and wishes to bear 50% more of the weight of the beam than his assistant. If one end of the beam is placed on the assistant’s shoulder, how far from the other end of the beam should the carpenter put his shoulder? [7]