Classical Mechanics Answers

Calculate the moment of inertia of the following figures:thick-walled sphere of the outer and the inner radii R and r

respectively, and mass m;

Calculate the moment of inertia of the following figures: solid ball of the radius R and mass m;

 A puck with a mass of 0.170kg has velocity of +90km/H. The momentum of the puck is ??

A 360 kg roller coaster car traveling at 18 m/s collides inelastically with a stationary 240 kg car on a section of a horizontal track. To what maximum height, h, do the combined cars travel before rolling back down the hill?

A 1.0 kg mass is attached to a horizontal spring which undergoes SHM. The graph of EPE as a function of position is shown. The total energy of the oscillating system is 0.8 J. 

What is the maximum displacement of the oscillating mass? 

d. What is the spring constant of the system? 

e. What is the potential energy at the position of 4 cm? 

f. What is the kinetic energy at the position of 4 cm? 

At a bottled water plant, water with a density of 1.00 g/ml passes through a pumping station where it is raised vertically by 5.23 m at the rate of 1,880,000 liters per day. The liquid enters and leaves the pumping station at the same speed and through pipes of equal diameter.

(a)Determine the output mechanical power (in W) of the lift station. Ignore any energy loss due to friction.

  W

(b)Assume an electric motor continuously operating with average power 3.85 kW runs the pump. Find its efficiency.

A 4.20–kg block is set into motion up an inclined plane with an initial speed of v_i = 7.40 m/s (see figure below). The block comes to rest after traveling d = 3.00 m along the plane, which is inclined at an angle of 𝜃 = 30.0° to the horizontal.

If I throw a ball up in the air it will eventually reach zero velocity before descending. My question is this: how long will the ball be at zero velocity? It seems to me that this time interval should be infinitesimally small. What am I missing?

1.     Two forces act on a parachutist during a drop. One force is the weight W(500N) of the parachutist. The other force is the upwards pull P(400N) from the parachute harness on the parachutist. The parachutist has a mass of 50 kg.

a.     What is the size of the unbalanced force acting on the parachutist?

b.     What is the acceleration of the parachutist?

1.     A boat engine produces a  force of 10000 N and the friction and water resistance total 3500 N.  If the mass of the boat is 2000 kg, what will be its acceleration?

1.     A student of mass 50kg climbs the college stairs using 2500J of energy, calculate the height of the stairs.

1.     An astronaut of mass 70 kg climbs to a height of 5 m on the moon and gains 560 J of gravitational potential energy. What must be the gravitational field strength on the moon?

1.     What is the speed of a stone of mass 2 kg if it has 36 J of kinetic energy?