Mechanics | Relativity Answers

In 100 seconds a smoke alarm emits 1000000 sound waves. What is the frequency of the sound waves

A man of mass 50kg carries a bag of weight 40N on his shoulder. The force with which the floor pushes up his feet will be

The elevators in the John Hancock building in Chicago move 783 ft in 33 s.
What is their speed? Answer in units of m/s

A hammer of mass 200g is dropped from the top of a roof of the two storey building to the ground. Another hammer of equal mass fell from a coffee table to the ground. Given than the height of the two storey building and the coffee table are 10 m and 5 m respectively.
a. Show that a hummer dropped from two storey building roof does more work than a hammer falling from a coffee table.
b. Calculate the potential energy from the two heights.

A source produces 400 waves every minute. If the speed of the waves is 8mm/s, calculate the distance between adjacent troughs.

What is the average velocity of the earth the instant it has traveled half of its circular orbit about the sun in m/s?

A golf ball is hit with an initial angle of 31.5° with respect to the horizontal and an initial velocity of 80.7 mph. It lands a distance of 86.8 m away from where it was hit. By how much did the effects of wind resistance, spin, and so forth reduce the range of the golf ball from the ideal value?

Runner A is initially 7.0 mi west of a flagpole and is running with a constant velocity of 5.0 mi/h due east. Runner B is initially 2.0 mi east of the flagpole and is running with a constant velocity of 4.0 mi/h due west. How far are the runners from the flagpole when they meet?

Two waves, travelling along the same direction, are given by
y1(x, t) = asin(w1t − k1x)
and
y2 (x, t) = asin(w2t − k2x)
Suppose that w1and k1 are respectively slightly greater than w2 and k2. i) Obtain an
expression for the resultant wave arising due to their superposition and ii) explain the
formation of wave packets.

Show that the direction cosine L,M,N of vectors Ax,Ay,Az is given by L=Ax/|A| , M=Ay/|A|, N=Az/|A| and hence L^2+M^2+N^2=1