Download Seminar 01

EP I
Winter Term 2014 / 2015
Exercises in Introductory Physics I
Seminar 1
October 22nd 2014
Measurement
1. The distance to one of the nearest fixed stars (Alpha Centauri) is 4.3 ×
1016 m.
(a) How long does a light signal travel from the star to earth? (1P)
(b) Calculate the angular diameter of the earth, one would observe from
that star. (1P)
2. One cubic centimeter of a typical cumulus cloud contains 50 to 500 water
droplets. These droplets have a typical radius of 10 µm. For that range,
give the lower and the higher values, respectively, for the following:
(a) How many cubic meters of water one will find in a cylindrical cumulus
cloud of height 3.0 km and radius 1.0 km? (1P)
(b) Water has a density of 1000 kg/m3 . What would be the mass of the
cloud? (1P)
Motion along a straight line
1. An object is thrown with an initial velocity of v0 = 5 m/s from a height of
15 m. Calculate the time until the object hits the ground for the following
two cases:
(a) It is thrown upwards. (1P)
(b) It is thrown downwards. (1P)
2. If the maximum acceleration that is tolerable for passengers in a subway
train is 1.34 m/s2 and subway stations are located 806 m apart from each
other:
(a) What is the maximum speed a subway train can attain between stations? (1P)
(b) What would be the travel time between stations? (1P)
(c) If a subway train stops for 20 s at each station, what is the average
speed of the train? (1P)
(d) Graph x,v and a versus t for the interval from one start-up to the
next. (1P)
Lecturer: R. Valiullin
Teaching Assistants: D. Schneider