Mechanics | Relativity Answers

An automobile traveling at 80.0km/hour has tires of 75.0cm diameter
A, what is the angular speed of the tires about their axles?
B, if the car is brought to a stop uniformly in 30.0 complete turns of the tires (without skidding). What is the magnitude of the angular acceleration of the wheels.
C, how far does the car move during the parking?

A 1000kg car has four 10kg wheels. When the cars moving what fraction of its total kinetic energy is due to rotation of the wheels about their axles? Assume that the wheels are uniform disks of the same mass and size. Why do you not need to know the radius of the wheels?

A 140kg hoop rolls along a horizontal floor so that the hoops center of mass has a speed of 0.150m/sec, how much work must be done on the hoop to stop it?

A uniform sphere of radius r= 0.500m and mass m= 15.0kg turns counter clockwise about a vertical axis through its center. Find its vector angular momentum about this axis when its angular speed is 3.00rad/sec.

A motor runs at 20rev/sec and supplies a torque of 75Nm. What house power is it delivering?

A fly wheel has a moment of inertia of 3.8kgm^2.what constant is required to increase its frequency from 2rev/sec to 5rev/sec in 6 revolutions?

The wheel on the grinder is a uniform 0.9kg disk of 8cm radius it costs uniformly to rest from 1400rpm in a time of 35 sec. How large a friction torque slows its motion?

A 500g uniform sphere of 7cm radius spins at 30rev/sec on an axis through its center find its
A, KEr
B, angular momentum
C, radius of gyration

A ball of mass 0.1kg is thrown vertically upwards with initial velocity of 80m/s.Calculate the potential energy ( I) halfway up(11) at its maximum height. What is it kinetic energy as it leaves the ground?.

1. A subway train is travelling at 80km/h when it approaches a slower train 50 m ahead
travelling in the same direction at 25 km/h. if the faster train begins to decelerate at 2.6
m/s2
. While the slower train continues at constant speed. How soon and what relative
speed will they collide. [8]

2. A farm decided to construct a portion of his area close to his house for chicken farming.
He decided to fence a rectangular area of length 4x and width of 3/2x^2, the length is
measured with uncertainty of 12 cm and width of 24 cm uncertainty. If the maximum
perimeter of this area is 350 m.
a) Find the length and width [6]
b) Calculate the area of this portion of land [2]
c) Calculate the percentage of uncertainty of the minimum area
[3]