Mechanics | Relativity Answers

A 4.9 kg rectangular air mattress is 2.7 m
long, 1.16 m wide, and 0.183 m thick.
What mass can it support in water before
sinking?
Answer in units of kg.

A hollow brass tube has outer diameter D =
3.1 cm. The tube is sealed at one end and
loaded with lead shot to give it a total mass
of M = 88 g. The tube floats in water (of
density 1 g/cm3) in vertical position, loaded
end down.
What is the depth of the bottom end of the
tube?
Answer in units of cm.

A container is filled with water to a depth of
47.3 cm. On top of the water floats a 46.2 cm
thick layer of oil with a density of 503 kg/m3.
What is the absolute pressure at the surface
of the water? The acceleration of gravity is
9.81 m/s2 .
Answer in units of Pa.

A pipe contains water at 5.6 × 105 Pa above
atmospheric pressure.
If you patch a 4.66 mm diameter hole in the
pipe with a piece of bubble gum, how much
force must the gum be able to withstand?
Answer in units of N.

Air within the funnel of a large tornado may
have a pressure of only 0.19 atm.
What is the approximate outward force F
on a 9.1 m × 26 m wall if a tornado suddenly
envelopes the house? Atmospheric pressure is 1.013 × 105 Pa.
Answer in units of N.

An engineer weighs a sample of mercury ( density= 13.6 × 103 kg/m3) and finds that the weight of the sample is 4.3 N.
What is the sample’s volume? The acceleration of gravity is 9.81 m/s2 .
Answer in units of m3.

A physics book measures 21.6cm x 27.9cm x 4.5cm. After 3 months of constant use, the top surface is displaced by a 35cm. Assume that the shearing force is 3.5N.
Find:
a. stress
b. angle of shear (radian unit)
c. shear modulus of the metal

I need the formula for calculating speed in a parabolic trajcetory with no air resistance. I need to reach a range of 20meters from a 45 degree angle. what speed do I need to be travelling at? I need the formula for future reference. Thank you.

The planet Mars has a mass of 6.1 × 1023 kg
and radius of 3.1 × 106 m.
What is the acceleration of an object
in free fall near the surface of Mars?
The value of the gravitational constant is
6.67259 × 10−11 N · m2/kg2.
Answer in units of m/s2.

Two balls, each with a mass of 0.764 kg,
exert a gravitational force of 9.00 × 10−11 N
on each other.
How far apart are the balls? The value
of the universal gravitational constant is
6.673 × 10−11 Nm2/kg2.
Answer in units of m.