PHYS 250 Exam 3 questions &
answers
Two children, Ahmed and Jacques, ride on a merry-go-round.
Ahmed is at a greater distance from the axis of rotation than
Jacques. Which of the following are true statements?
a. Jacques has a greater angular speed than Ahmed.
b. Jacques and Ahmed have the same angular speed
c. Jacques has a smaller angular speed than Ahmed
d. Jacques and Ahmed have the same tangential speed - answer b
The figure shows scale drawings of four objects, each of the same
mass and uniform thickness, with the mass distributed uniformly.
Which one has the greatest moment of inertia when rotated about
an axis perpendicular to the plane of the drawing at point P? (This
is a conceptual questions. No calculation or formula is needed.)
A
B
C
D - answer b
A rubber ball and a lump of clay have equal mass. They are
thrown with equal speed against a wall. The ball bounces back
with nearly the same speed with which it hit. The clay sticks to
the wall. Which one of these objects experiences the greater
momentum change?
, a. Both of them experience the same non-zero momentum
change
b. Both of them experience zero momentum change
c. the ball
d. the clay - answer d
When a car is weighed, it is driven slowly on a horizontal floor
over a scale that records a reading as the front wheels go over
the scale, and then records a second reading as the rear wheels
go over the scale. The weight of the car is equal to
a. the weight under the front wheels
b. the difference of the 2 weights
c. the sum of the 2 weights
d. the average of the 2 weights - answer c
During World War I, Germany used a "Big Bertha" cannon to hurl
shells into Paris 30 miles away. This gun also had a very long
barrel. What was the reason for using a long barrel in these guns?
a. exert a larger force
b. to reduce frictional losses
c. to reduce the force exerted on the bullet due to the expanding
gases from the gunpowder
d. to allow the force of the expanding gases from the gunpowder
to act for a longer time - answer d
answers
Two children, Ahmed and Jacques, ride on a merry-go-round.
Ahmed is at a greater distance from the axis of rotation than
Jacques. Which of the following are true statements?
a. Jacques has a greater angular speed than Ahmed.
b. Jacques and Ahmed have the same angular speed
c. Jacques has a smaller angular speed than Ahmed
d. Jacques and Ahmed have the same tangential speed - answer b
The figure shows scale drawings of four objects, each of the same
mass and uniform thickness, with the mass distributed uniformly.
Which one has the greatest moment of inertia when rotated about
an axis perpendicular to the plane of the drawing at point P? (This
is a conceptual questions. No calculation or formula is needed.)
A
B
C
D - answer b
A rubber ball and a lump of clay have equal mass. They are
thrown with equal speed against a wall. The ball bounces back
with nearly the same speed with which it hit. The clay sticks to
the wall. Which one of these objects experiences the greater
momentum change?
, a. Both of them experience the same non-zero momentum
change
b. Both of them experience zero momentum change
c. the ball
d. the clay - answer d
When a car is weighed, it is driven slowly on a horizontal floor
over a scale that records a reading as the front wheels go over
the scale, and then records a second reading as the rear wheels
go over the scale. The weight of the car is equal to
a. the weight under the front wheels
b. the difference of the 2 weights
c. the sum of the 2 weights
d. the average of the 2 weights - answer c
During World War I, Germany used a "Big Bertha" cannon to hurl
shells into Paris 30 miles away. This gun also had a very long
barrel. What was the reason for using a long barrel in these guns?
a. exert a larger force
b. to reduce frictional losses
c. to reduce the force exerted on the bullet due to the expanding
gases from the gunpowder
d. to allow the force of the expanding gases from the gunpowder
to act for a longer time - answer d
