practice problems for ex 1 fall18.doc - 1. How large a...

1. How large a force is necessary to stretch a 2.0-mm-diameter steel wire ( E = 2.0  10
11
N/m
2
) by 1.0%?
N
2. Crew members attempt to escape from a damaged submarine 80 m below the surface. What force must they
apply to a pop-out hatch of radius of 18 cm to push it out? Assume the density of ocean water 1025 kg/m
3
.
3. A cylindrical submarine with mass 20 x 10
5
kg , radius of 2.75 m and length of 100 m is anchored to the
bottom of a channel as shown schematically in the figure. What is the tension in the cable assuming the
submarine is totally submerged?
N 4. A 1500 g block of wood floats in a container of oil (the oil’s density is 750 kg/m
3
). What volume of
oil does the wood displace?
5. A sample of unknown material appears to weigh 300 N in air and 200 N when immersed in water. What is
the density of the material? (the density of water is 1000 kg/m 3
3