In: Physics
1) a)Godzilla crushes a subway car between his two hands by pressing against its ends. The force applied at each end can be described as
options:
a tensile force
a compressive force
a shearing force
a bulk force
a and b
b) You place your flat hand on top of a textbook which is lying flat on the desk. You gently push against (along) the book cover in the direction parallel to the surface of the desk, causing the shape of the book to distort slightly. The parallel force you applied can be described as
options:
a tensile force
a compressive force
a shearing force
a bulk force
a and b
c) Two teams stretch a rope in a game of tug-of-war. The applied force from each of the two teams can be described as
options:
a tensile force
a compressive force
a shearing force
a bulk force
a and b
d) The units of Young's modulus, the shear modulus, and the bulk modulus are
options:
all N/m
all N/m2
all N/m3
N/m, N/m2, N/m3
all dimensionless
e) Stress divided by strain has units of
options:
Newtons
Newton meter
Newton per meter
Newton per square meter
none; it's dimensionless
Tensile force occur when we try to stretch an object along its length, for example pulling a rope
Compressive force occur when we compress an object from two opposite sides
Shearing force occur we applied force is parallel to the surface of object, this distort the object
Bulk Force act on object when we try to compress from all direction with equal force.
(a) Since godzilla is compressing car from two opposite sides (hands) so this is a compressive force
(b) Since force is parallel to surface of book hence it is a shearing force
(c) In tug of war we stretch the rope along its length hence it is a tensile force
(d) Unit of stress is whereas strain is dimensionless. And all modulus is given as stress/strain so unit of Young's modulus, the shear modulus, and the bulk modulus are all
(e) Stress = Force/area hence unit is , strain = change in length/original length so unitless so unit of stress divided by strain is Newton per square meter