Search & Filtering
Calculate the volume of water (in cm3 ) that overflows when a Pyrex beaker filled to the brim with 250 cm3 of water at 20 oC is heated to 60 oC. **Do not enter the units.
Coefficients of Volume Expansion:
Substance Coefficient ×10−4 /oC.
Water 2.1
Pyrex glass 0.09
**Do not enter the units in your final answer
Problem Solving: Show your complete Solution.
- In an atom an electron moves about its nucleus in a circular path of radius 5.30 x 10-11 m, with a speed of 2.20 x 106 m/s. Find the acceleration of the electron and the centripetal force. (mass of electron = 9.11 x 10-31 kg)
2.A ball weighing 1.5 kg is whirled in a circular path at a speed of 12.0 m/s. If the radius of the circle is 5.6 m, what is the centripetal force?
A futile task is proverbially said to be “like trying to empty the ocean
with a teaspoon.” Just how futile is such a task? Estimate the number of
teaspoonfuls of water in the Earth’s oceans.
I answered this exercise by using Fermi calculations.
First of all, I used an estimation of all amount of water in the Earth which is V = 1021L. Secondly, 1 tea-spoon = 5 mL = 5x10-3L. Next, we will divide 1021L/5x10-3L ,so the number of tea-spoons in all water in the Earth is approximately N = 2 x 1023. Besides, I answered the question Just how futile is such a task? by calculating the time is taken to empty all the water in the Earth.
I assumed 1 tea-spoon = 5mL to empty = 1s
then,
t = (2 x 1023)(1s) = 2 x 1023s = 6 x 1013 centuries
This time is impossible to be spent by human or a machine.
I think that my answer is right, but I only want to check because I used the same strategy that I showed in the exercise above in all Fermi Exercises and Calculations in my book.
A uniform solid cylinder, sphere and hoop roll slipping from rest at the top of an incline. Find out which object would reach the bottom first
A cylinder of mass m and radius R has a moment of inertia of 1/2mr^2. The cylinder us released from rest at a height h on an inclined plane, and rolls down the plane without slipping. What is the velocity of the cylinder when it reaches the bottom of the incline?
A 400.0-N sign hangs from the end of a uniform strut. The strut is 4.0m long and weighs 600.0 N. The strut is supported by a hinge at the wall and by a cable whose other end is tied to the wall at a point 3.0m above the left end of the strut. Find the tension in supporting cable and the force of the hinge on the strut
How Electromagnetic Waves behave in...
Vacuum?
Optical Medium?
A person is jumping from a height ℎ0 = 10 m with zero initial velocity and a cricket ball is thrown directly upward with an initial velocity 𝑣𝑣0 = 9.8 m/s at the same instant when time t = 0 s as shown in Fig. 1. Consider h = 11.5 m and 𝚤𝚤̂and 𝚥𝚥̂ to be the unit vectors along the X and Y axis. Gravity is acting along the -𝚥𝚥̂direction and the magnitude of gravitational acceleration is given by g = 9.81 m/s2 . The red dot on the person represents his center of mass.
(a) (4 marks) If the person and the cricket ball consist of a system, find the position and velocity of the center of mass of the system at time t = 0.5 s.
(b) (2 marks) If it takes 0.01 seconds for the person to come to complete rest when he hits the ground, calculate the average force acting on the person.
(c) (4 marks) Now consider when the person hits the ground, he bends his knees such that the center of mass of his body is lowered by 15 cm. If the maximum force that the bone of his legs can withstand is 50000 N, will he break his legs?
2. At a sharp horizontal circular turn a train slows down going from 90.0 km/h to 50.0 km/h in the 15.0 s it takes to round the bend. The radius of the curve is 150 m. Assume the train continues to slow down at the same rate. At the moment the train speed reaches 50.0 km/h calculate:
(a) (3 marks) the magnitude and direction of the tangential acceleration.
(b) (3 marks) the radial acceleration (magnitude and direction).
(c) (4 marks) the magnitude and direction of the total acceleration.
Calculation of Lattice Cell Parameters – X-ray Diffraction
