Almaseera School
Physics – 11A
Ms. Fatima Alketbi
6.7) Non- conservative force and work – energy theorem
1 A 30.0-kg crate is pushed across a rough floor by a horizontal force of 100 N.
The coefficient of kinetic friction between the crate and the floor is 0.100. If a
total of 80.5 J of work is done on the crate, how far was it moved along the
floor?
A. 0.840 m
B. 1.14 m
C. 1.64 m
D. 2.04 m
E. 2.44 m
2 An 80-kg fireman slides down a 3-meter pole by applying a frictional force
against the pole using his hands. If he slides from rest and he land on the
ground with a speed of 6.00 m/s, the frictional force his hands applied against
the pole was
A. 423 N.
B. 581 N.
C. 735 N.
D. 305 N.
E. 912 N
3 A 3-kg block slides down a smooth incline of length 2 m inclined at 30 and
hits a level, horizontal rough patch, coming to a stop in 1 m. What is the
coefficient of friction between the block and the rough patch?
A.
B.
C.
D.
E.
0.25
0.5
0.33
1.0
0.75
4 A 5-kg block of ice travels with a speed of 12 m/s when it hits a 25 incline
plane. How far does it travel frictionlessly up the plane?
A. 12.3 m
B. 7.3 m
C. 5.6 m
D. 13.7 m
E. 17.4 m
Almaseera School
Physics – 11A
Ms. Fatima Alketbi
5 A tennis ball of mass 70 g is thrown vertically upward at 25 m/s. It rises to a
height of 21 m. The work done by the resistive forces is
A. -18.1 J.
B. -7.5 J.
C. -6.2 J.
D. -3.5 J.
6 A 5.0-kg pumpkin is dropped from the top of the RCA Building in New York
City. If it falls through a distance of 380 m, and splats on the sidewalk with a
speed of 52.0 m/s, what is the work done by air resistance during its fall?
A. 12 kJ
B. -12 kJ
C. 19 kJ
D. -19 kJ
7 How much mechanical energy is lost to friction if a 22-kg box slides 7.0 m
down a rough inclined plane at a constant speed of 11 m/s? The inclined plane
makes an angle of 33 degrees with respect to the horizontal.
A. 820 J
B. 920 J
C. 1300 J
D. 1500 J
E. 1700 J
8 I push an object along a horizontal surface a distance d with a force F at an
angle
A.
B.
C.
D.
E.
. If the velocity is constant at a value v, then
there is no net work done.
the net work done is Fdcos .
the net work done is Fdsin .
you cannot calculate the net work.
the net work done is Fv.