Classical Mechanics Answers

An object is moving along the plain surface by the force F = (5x)i - (3y)j.
a) How much work was done if the particle moved from (0,0) to (-6,8)?
b) What is the change in kinetic energy?
c) If the change in location occurred in 0.2 seconds, what is the average power?

A body of mass 12kg is projected vertically upwards and made a trajectory with base length 8m for 3secs when the body is projected vertically downwards it dropped into a cylinder containing a liquid of relative density 0.92 if the distance traveled by the body vertically downwards is given as y=3t
4
−4t
3
−8
Find
1. The weight of the body
2. The density of the liquid
3.The maximum height of the projected body
4.The angle of projection

In loading a delivery van a driver pushed a 15 kg crate for 5 metres up a ramp. He had to push with a force of 132N and the vertical height gained was 1.3m. What was the efficiency of pushing this crate up the ramp onto the back of the van

Special delivery trucks, which operate by making use of the energy stored in a rotating flywheel, have been in use for some time. The trucks are “charged up” before leaving by using an electric motor to get the flywheel up to its top speed of 7000 revolutions per minute. If one such flywheel is a solid cylinder (I = 1/2 MR2) of weight 5000 N and a diameter of 2 m, how long can the truck operate before returning to base for “recharging,” if its average power requirement is 8000 Watts? (Watt = Joule/second)

A wheel is rotating freely at an angular speed on a shaft.A second wheel with twice the moment of inertia of the first and initially at rest is suddenly coupled to the first shaft. If K is the original rotational kinetic energy and Delta K is the loss in rotational kinetic energy then (∆K)/(K) is
Ans 2/3

A rocket of mass 0.41 kg is set on the ground, pointing vertically up.
When ignited, the gunpowder burns for a period of 1.6 seconds, and provides a constant force of 16 N.
The mass of the gunpowder is very small compared to the mass of the rocket, and can be ignored.
The effects of air resistance can also be ignored. Use g = 9.8 m s-2. Answer accurate to 0.1 N.

What is the magnitude of the resultant force on the rocket?

An archer shoots an arrow from a height 4.2 m vertical height from the ground with a speed 40m/s and at an angle 30° to horizontal level Determine the horizontal distance R' covered by the arrow when it hits the ground.(Let g=10m/s²)
Ans 84√3

by using jean number and average energy derive planks law of radiation

A 15m wide horizontal platform is suspended by ropes at each end, each capable of withstanding tension of 122kN. The uniform concrete platform has mass 1500kg.
a) Calculate the maximum load that can be added to the centre of the platform.
b) Calculate the maximum load that can be added to the extreme end of the platform.
c) Explain why these two calculations produce different values.
d) Suggest a value for the maximum safe recommended load for the platform and justify.