Classical Mechanics Answers

We fill an entire a 15cm deep glass with kerosene. What is the pressure that the fluid exerts on the bottom of the glass –

A mass is on a level plane it has a weight of 20N. A horizontal force of 7.3N causes the mass to begin slipping. Calculate the coefficient of static friction between the two surfaces

A body hanging from a spring is set into motion and the period of oscillation is to be 0.8sec. After the body has come to rest it is removed. How much shorter will the restoring force be when it comes to rest?

The energy delivered by an asteroid impact.

(a) A small asteroid weighs about 1012 kg. If its density is twice that of water, roughly what is the size (diameter) of the asteroid, in meters?

(b) The asteroid travels at a speed of about 10 km s−1 relative to the earth. How much kinetic energy (in Joules) would be released if the asteroid hit the earth?

(c) Convert the previous result to Calories.

(d) Suppose the asteroid lands in a roughly circular lake, about 10 km across and 10 m deep. If all the asteroid’s kinetic energy is converted into heat energy of the water in the lake, by how many degrees Centigrade will the lake warm-up?

(e) If the asteroid had been going twice as fast, how would this affect the amount of energy released on impact?

The 3th overtone of one end fixed string produce a frequency of 72Hz and the
length between a node and the adjacent anti-node is 5cm.waht is:
(a) the length of the string ?
(b) the wave length in this overtone and in the 1st overtone?
(c) the wave speed ?
(d) the fundamental frequency?
(e) the longest wavelength?

A simple pendulum of length 1m makes 400 complete oscillations in 8s at a certain place. If another pendulum makes 100 complete oscillation in 1s at the same place.
Find the length of the second pendulum.

On a hot summer afternoon, Keith and Nate are out fishing in their rowboat when they decide to jump into the water and go for a swim. Keith, whose mass is 65.0 kg, jumps straight off the front of the boat with a speed of 2.00 m/s relative to the boat, while Nate propels his 68.0-kg body simultaneously off the back of the boat at 4.00 m/s relative to the boat. If the 100.-kg boat is initially traveling forward at 3.00 m/s, what is its velocity after both boys jump?

If you dropped the pencil one more time, do you think it would be more likely to land near the center or near the edge of the circle?

The kinetic coefficient friction of a rubber tire on wet concrete is 0.70. What is the mass of a tractor that with its brakes locked, can be dragged by a tow truck exerting a horizontal force of 1.0 x104 N?

A 1kg mass hangs at the end of a spring, stretches the spring by a distance X from
the equilibrium position. If the mass is increased by 9gm, the displacement
increases by 10cm.
a) what is the force constant of the spring?
b) If the spring vibrates in SHM, find the ration of frequencies in the two cases.