Transcript QuizFeb07

Period 2
Question 1
As a car skids with its wheels locked trying to stop on a road covered
with ice the force of friction between the icy road and the tires usually
will be
1.
2.
3.
4.
greater than the normal force of the road times the
coefficient of static friction
equal to the normal force of the road times the coefficient
of static friction
equal to the normal force of the road times the coefficient
of kinetic friction
less than the normal force of the road times the coefficient
of kinetic friction
Period 2
Question 2
A brick slides on a horizontal surface. Which of the
following will increase the frictional force on it?
1.
2.
3.
4.
Putting a second brick on top
Decreasing the surface area of contact
Increasing the surface area of contact
Decreasing the mass of the brick
Period 3
Question 1
In case A a box is dragged along a horizontal surface,
in case B it is dragged up an incline by a force
parallel to the incline. The frictional force in case B,
as compared to case A, is:
1.
2.
3.
4.
Always the same
Always greater
Always less
Less for some angles, larger for others
Period 3
Question 2
A ball is thrown downward from the edge of a cliff with an initial
speed that is greater than the terminal velocity. Initially the ball’s
acceleration is
1.
upward acceleration
2.
no net acceleration
3.
downward, acceleration less than g
4.
downward, acceleration greater than g